The Science syllabus covers areas in Science, Home science and Agriculture.

In the first three sessions of this INSET, the three areas have been integrated in line with the integrated primary science syllabus. In the next three sessions the three science subjects are separately.

In the course of the training the learners are expected to enhance their acquisition scientific knowledge, skills and attitudes. To achieve this learners are exposed to adequate practical activities.

Besides the coverage in class assignment and projects, the learners are to be exposed to a variety of teaching methods and resources. The topics have been given in the order in which they are to be covered in subsequent sessions and the duration expected for each topic.

General objectives

At the end of the course, the learner should be able to:

  • (i) Demonstrate acquisition of adequate scientific knowledge which will improve competence in handling primary science.
  • (ii) Demonstrate and apply the scientific process skills and technology necessary for solving problems.
  • Acquire attitudes necessary in the problem solving process.
  • Use locally available resources necessary for science learning.
  • (v) Adopt practices for sustainable use of the environment.
  • Foster practices that will enhance physical and mental health.
  • Identify and utilize opportunities for productive work in the college, home and community.
  • Develop creativity and critical thinking in addressing new emerging challenges.
  • Use a variety of strategies that stimulate the learner to investigate.
  • (x) Use locally available materials for improvisation
  • Demonstrate the ability to use teaching/learning resources to promote sound science learning in children.
  • Use the principles and skills acquired as a foundation for further education and training in various fields.
  • Apply skills, knowledge and attitudes to improve the standard of living for self, family and community.
  • Measure and evaluate learning outcomes.






  • SOIL
   7  HOURS
  7  HOURS
  8  HOURS
  9  HOURS







1.1   Introduction

In this topic we are going to find out what is Science; what different science from other subjects, what methods to use in science.  We are also going to find out what skills and attitudes that one should have when learning science.

1.2 Objectives

By the end of this topic, you should be able to;

  • Define science
  • Explain static and dynamic views
  • Describe the scientific process skills and attitudes.
  • Identify different methods of recording in science.
  • Apply problem solving skills to the burning candle and pendulum experiment.
  • Acquire scientific attitudes as they perform the burning candle and pendulum experiment.
  • Acquire scientific attitudes as they perform the burning candle and pendulum experiments.

1.3 Subtopics

  • What is science/philosophy of science
  • Definition of science
  • Nature of science (static/dynamic view)
  • Problem solving process
  • Scientific skills and attitudes

1.4 What is science?

Philosophy of science is a branch of philosophy concerned with the foundations, methodsand implications of science.

  • Its concerns what qualifies as science, what is science, purpose of science, difference between science and other subjects and is there a scientific method.

Activity:  In groups let everyone write down in a paragraph what is science and each group presents.

1.5  Definition of Science

Many definitions exist and include

  • Science is a method of acquiring knowledge through carrying out activities.
  • Science is organized knowledge acquired through system observation and testing of facts about the physical world, natural laws and living organisms.
  • Science is a study that involves establishing of facts, principles and methods through experiments.

1.4  Nature of Science

Refers to approaches or views of teaching science.

There are two views

Static view

Dynamic view

Activity:  (i) Give the meaning of the terms ‘static and dynamic’

(ii) Give examples of everyday usage of words.

Static view

  • Sees science as a lobby of knowledge /concepts to be observed and passed on from generation to generation.
  • Considers science as a way of explaining universe.
  • Emphasizes theories, laws and principles
  • Presents systematized information
  • Science is considered as a way of internalizing formulated statements and facts.
  • Argues that learning science can be done without practical approach.

Teachers using this view to teach science will;

  • Prepare elaborate notes
  • Ensure proper note taking
  • Rarely do activities
  • Require learners to listen and comply


Advantages of static view

  • Cheap because it requires fewer resources
  • Wide coverage of syllabus
  • Easy to conduct for teacher
  • Class control is easy
  • Good for large classes


  • Teacher centered
  • Learners easily forget what is learnt
  • Few skills and attitudes developed
  • Does not create interest in learners

1.42  Dynamic View

  • Considers science as an activity
  • Looks at present state of knowledge as a basis for further investigations.
  • Sees investigations as key in science.
  • Emphasizes use of scientific skills in problem solving
  • see science as a continuous search of knowledge
  • Allow the possibility that what is recorded as true can change.


Teachers who use this view to teach science will:

  • Act as a guide in learning science
  • Believe pupils have ability to find out
  • Engage pupils in experiments and practical’s
  • Initiate collection of materials for pupils to work in a class.

Advantages of dynamic View

  • Learners are engaged in activities
  • Creates interest in learners
  • Develops scientific skills and attitudes
  • High retention of knowledge
  • Can help solve scientific problems.

Disadvantages of dynamic View

  • Time consuming
  • It’s expensive because it requires more resources
  • Requires detailed planning by teacher
  • Difficult to use with large groups


Question:  Does the definition of science support the static or dynamic view?



Advantages of static view

  • Cheap because it requires fewer resources
  • Wide coverage of syllabus
  • Easy to conduct for teacher
  • Class control is easy
  • Good for large classes


Disadvantages of static view

  • Teacher centered
  • Learners easily forget what is learnt
  • Few skills and attitudes developed
  • Does not create interest in learners.



A skill is the ability to do something well.

Skills can be either manual or mental and are acquired through a practice.

Scientific skills are abilities learners need to acquire as they learn science.

They include:

(i) Observation – employs senses to perceive objects or events

– Must select out what is important in investigation

–  Skill can be developed in learners by engaging them in activities to practice using their senses.


(ii)  Recording – Information gathered or observations made are recorded and stored for.

  • Future reference
  • Communication information to others
  • Enable analyses of information and drawing conclusions
  • Help to make predictions

Methods of recording include-:

  • Note making
  • Drawing diagrams
  • Mounting
  • Tabulation
  • Modeling
  • Using graphs
  • Photographs
  • Audio and Audio-visual recording
  • Printing

Question:  Identify methods of recording suitable for lower and upper primary.


(iii)   Asking questions – helps learners to seek information think and sort out after observation.

  • The skill helps learners to learn more and get clarification.

(iv)   Sorting and classifying

  • Sorting involves putting things separately due to differences and similarities.
  • Classifying involves arranging things according to their characteristics.

Question: What is the relationship between sorting and classification?

(v)  Measuring – Involves finding out size, weight, quantity etc.

-Involves use of instruments e.g. ruler, weighing scales, thermometers etc.

– It allows one to make conclusions

-Younger children measure by estimation

Question:-  Give activities you would engage in class to develop the skill of measurement?

(vi)  Drawingconclusion – involves making decision on basis of observations, conclusions can         also be a basis for further investigations.

(vii)  Communication involves passing information gathered to others.

  • It allows other people to give you a feedback.
  • Learners communicate by drawing, modeling, writing, painting, speaking, group discussion, student presentation etc.

(viii) Counting – involves allocating numbers to objects.

  • Can be used in making observation and recording.

(ix)  Formulating hypothesis

-Involves suggesting an explanation and then testing it by experiment.

(x)  Prediction – To test hypothesis predictions are made.

-It foretells what is likely to happen

– Must be based on careful observation of past events and patterns.

(xi)  Manipulating –  involves physical handling of apparatus or materials appropriately.

  • Usually a manual skill and therefore developed by engaging learners in hands on activities.

(xii) Designing experiments –

-Involves setting an experiment to practically carry out investigation.

– Design depends on problem to be solved and hypothesis formulated.

(xiii)  Controlling variables

A variable is a measurable factor which can be altered during experiment.

In experiment we have:


-Independent variable is the one that is controlled and manipulated by the experimenter.

– Dependent variable is the factor that changes as a result of altering the independent


– Constant variables – factors that are maintained the same during experiment.

In experiments we have a test experiment and a control experiment.

Question:  Differentiate between a test experiment and control experiment?

(xiv)  Inferring – ability to reach an opinion based on available evidence.

  • Inferences help solve problems and predict future events.




An attitude is a mental predisposition towards people, objects, subjects, events etc.

  • A learner’s attitude carries a mental state of readiness.
  • A learner with positive attitude will perceive science objects, topics, activities and people positively
  • Attitudes are learned and organized through experiences as children develop.
  • Teachers have a great influence on a learner’s science attitude.
  • Teacher’s role is to preserve positive attitudes in children and develop new ones which do not develop naturally.

The attitudes include:-

(i)  Curiosity – Children are naturally curious and when playing will try to answer the

what would happen if?

  • Curiosity makes learners inquisitive which is needed in learning science.
  • Teacher should strive and keep the natural curiosity in learners alive as they grow older.

Question: – In groups discuss how the teacher can enhance the attitude of curiosity in learners.


(ii)  Genuine Interest:-

Interest is a desire to learn or hear more or be involved in something.

Genuine interest is the desire of the learner to carry out an activity with the right motive.

  • Learners should do activities to learn and not to please the teacher.
  • To develop this attitude the teacher should create conducive learning atmosphere.
  • Genuine Interested learners ask questions readily
  • Bring resources required
  • Apply what the learn
  • Carry out activities without supervision

(iii)  Self-confidence – an inner feeling that one has the ability to succeed when they carry out a


  • It gives one the will power to carry out a task.
  • Develops as one successfully accomplishes a task

Question: – State ways in which a teacher can develop this attitude in learners

(iv) Co-operation -Willingness to work together with others to achieve a common goal.

Develops as one appreciates other individuals who have different talents i.e.potentials that can benefit group members.

  • Skill is developed by engaging learners in group work during activities.
  • Every learner should be given a task which will contribute to completion of activity

(v)  Responsibility – Implies one can be relied on to carry out a given task as instructed.

– Can be developed in learners by giving them different tasks during activities.

Question: – State ways through which co-operation can be enhanced in group work.

(vi)  Open-mindedness

  • Willingness to listen to views contrary to your own
  • In science, there are no perfect answers in investigations.

Learners therefore need an open mind to learn science.

A pupil with an open mind:-

  • is willing to change mind in face of new reliable evidence
  • Respects other people’s points of view.
  • Looks at a problem from many sides
  • Only concludes after gathering enough evidence.

(vii)  Practical approach to solving problems

–  Developed by encouraging learners find answers to their own questions

–  Pupils with this attitude seek their answers using the problem solving approach.

–  Teachers role is to direct the learning process and give direction to enable learners

to arrive at possible answers.

1.8:  Application of Problem Solving Skills To Burning Candle And Pendulum Experiment

1.8.1:  Burning Candle Experiment

Problem:  What fraction of air is used during burning?

Instructions: -You have been provided with the following materials per group;

  • (i) Candle
  • (ii) Match box
  • (iii) Trough
  • (iv) Water
  • (v) Clear glass jar
  • (vi) Ruler
  1. a) Using the materials provided;

-Write down the procedure you will use to successfully carry out the experiment.

Question:  Write down three questions that will guide you in making your observations

  1. b) Predict what would happen
  • (i) If a larger glass jar is used to cover the candle
  • (ii) If two candles are used instead of one
  1. c) Identify skills and attitudes that can be enhanced in learners when performing this experiment.

1.8.2:  The Pendulum Experiment

Problem:  Does the angle of release of pendulum affect the number of oscillations?

You have been provided with the following materials in your groups.

  • Support
  • Weight
  • Strings
  • Metal bob


  • (i) Tie the metal bob with the string and fix it to the support
  • (ii) Release the metal bob at different angles and count, then record the number of oscillations.

From your results what is the relationship between the angle of release and the number of


Question: – Does the length of the string affect the number of oscillations.

Design an experiment to answer this question.







  • Explain the methods of teaching Science.
  • State the various teaching/learning resources.
  • Construct teaching/learning resources
  • Improvise teaching/learning materials
  • Prepare a Scheme of Work and Lesson Plan.
  • State the meaning and purpose of Assessment
  • Explain the different methods of Assessment
  • Identify the different types of tests
  • Describe levels of mental ability
  • Construct a table of specification
  • List down the characteristics of a good test.
  • Construct different test items’

Analyze past K.C.P.E. test papers



2.2.3 Questioning Technique

This is an important technique that a teacher can use to effectively engage learners in a lesson

Purpose of asking question

  1. To find out whether a learner has understood what has been taught
  2. To find out the background knowledge a learner has before teaching(diagnostic)
  3. To enhance participation of learners in a lesson {stimulate interest] in learners.
  4. To seek more information from a learner {probing and clarification}
  5. Develop critical thinking in learners by asking higher order question and their problem solving skills.
  6. To identify and correct learners misunderstanding{misconceptions}


Qualities of A Good Question

  1. They should be clear
    • Learner should understand what the question requires .They should not be ambiguous.
  2. Should be suitable
    • Use appropriate language for that level of learners.
    • Relevant to what has been taught.
  3. Have appropriate length {precise}-especially the stem.

Effective questioning strategies

  1. Create a conducive atmosphere for learners’ participation
    • Respond to learners’ response in a non –threatening manner.
    • Respond to learners response positively e.g nod, complicating and corrections which are not harsh.
  1. Use both preplanned and emerging questions.
  • Those planned during lesson planning.
  • Follow –up questions from discussions for probing, refocusing etc
  1. Use questioning to develop the various cognitive levels {Bloomstaxonomy}
  • Recall of facts /knowledge
    • Comprehension
    • Application
    • Analysis
    • Synthesis
    • Evaluation

Don’t always dwell on recall of knowledge but develop critical thinking skills by asking questions from the other levels

  1. Avoid questions that just require a Yes or No answer
  • They deny the learner an opportunity to justify or give a reason for his answer
  1. Phrase question clearly
  2. Have sufficient wait time
  • Give learners 5-10 sec to think and respond to your questions
  1. Address a question to the whole group and then identify the one answer
  2. Respond to learners’ response


  • Practical Work
  • Experimentation
  • Demonstration
  • Discussion
  • Science Walk
  • Field Trip
  • Lecture
  • Project
  • Dramatization/Role Play


  • Types of Resources
  • Preparation of Learning Resources


  • Purpose of Scheme of Work
  • Factors to Consider when Writing a Scheme of Work
  • Component of a Scheme of Work
  • Preparation of a Sample Scheme of Work
  • Reasons for Stating Skill, Knowledge and Attitudinal Objectives.


  • Purpose of a Lesson Plan
  • Main Components of a Lesson Plan
  • Preparation of a Sample Lesson Plan


  • Meaning of Assessment
  • Purpose of Assessment
  • Methods of Assessments
  • Different Types of Tests
  • Characteristics of a Good Test
  • Construction of Tests
  • Demonstration Teaching



Recent findings in the learning of Sciences emphasize the importance of using inquiry-based approach to teaching and learning.


The power of an inquiry-based approach to teaching and learning is its potential to increase intellectual engagement and foster deep understanding through the development of a hands-on, minds-on and research-based towards teaching and learning.


Inquiry provides opportunities for both teachers and pupils to collaboratively build, test and reflect on their learning.  As contrasted with more tradition forms of teaching and learning, inquiry emphasizes the process of learning in order to develop deep understanding in learners in addition to the intended acquisition of content knowledge, skills and attitudes.


Curriculum implementation is a process and in this unit you will learn about the professional documents the teaching methods and the resources required by the Science teacher.



2.1   Practical Work

Quality practical work can engage students, help them to develop important skills, help them to understand the process of scientific investigation and develop their understanding of concepts.


A good practical task is one that achieves its objectives of effectively communication a clearly defined set of ideas.  A good question to consider before planning to carry out any practical activity is:

What do I expect the learners to learners to learn by doing this practical task that they could not learn at all, or not so well, if they were merely told what happens?  Asking this question will help to define the objectives of the activity and justify its use.


  • Skills development
  • Experimental learning
  • Pupils confidence
  • Manipulation of materials and objects
  • Observing using all senses
  • Working in teams
  • Development of scientific attitudes when using this method the teacher should
  • Avail the teaching/learning resources
  • Discuss instructions/procedure on how the activity will be conducted.
  • Involve the learners in the practical and use relevant questions stop promote thinking and direct pupils observations.
  • Discuss learners observations
  • Ensure learners record their observations using the most appropriate method.
  • Ensure the safety of learners


Most of the topics in the Primary Science Syllabus can be taught using practical work.

Early experiences in practical science work help the learners to develop problem-solving skills that empower them to participate in an increasingly scientific and technological world.


2.2   Experimentation

An experiment is something we do in order to test the truth of an idea or a statement.It is important that children should discover that they can test the truth or a statement by doing a recommended activity.

Experiments from the foundation of the science curriculum.  The practical work captures and retains the interest of young pupils and makes the phenomena studied more real and interesting.

The purposes of developing experimental skills during the teaching of primary school science are to:

(a)  Encourage accurate observation and careful recording

(b)  Promote a simple common sense scientific method of thought.

(c)  Develop manipulative skills

(d)  Give training in problem solving

(e)  Explain observations and aid comprehension

(f)  Arouse and maintain interest in pupils.

(g)  Making, biological, chemical and physical phenomena clearer through actual experience.



In any experiment you intend to use in your teaching, either as demonstration or pupils themselves, plan well in advance to prevent

  • Waste of time
  • Accidents and ensure that pupils
  • Ensure that pupils will experience as much as possible.


If the equipment is not sufficient and depending on the subject, you may be required to group the pupils.  But the size of such a group will depend on the materials available.  In such groups, the participation of each individual pupil should be ensured.  You should in other words, involve the pupils as much as possible in the setting up of the experiments.

In most cases experiments will serve in the presentation phase of the lesson, and therefore the following procedure is suggested.

  • After discussion of the topic, confront the pupils with the problem to be investigated.
  • Develop the procedure for the experiment that will be suitable for use with the materials available. Children should be involved as much as possible.  They should contribute to the design of the experiment.
  • Demonstrate the correct way of handling of apparatus and materials, but NEVER give away.
  • Give directions for the recording of the experiment. Children should be allowed to propose the suitable method for this.
  • Describe how the cleanup is to be carried out and how waste materials are to be removed.
  • Have a pupils re-state the purpose or aim of the experiment.
  • Give signal for group work to begin.
  • Supervise from work place to work place.
  • Announce the time for stopping the work and cleanup.
  • Discuss pupils’ observations, pupils should be given opportunity to report and record their observations.
  • From all the results help the pupils to formulate a statement (s) or the class’s findings.



A demonstration is any planned practical performance by the teacher based on a scientific activity or experiment.


As a teaching technique, a demonstration is available alternative TQ getting pupils to learn by doing.  While learning by doing is ideal. Adopting this approach is not always possible with large number of pupils for example the time, space and resources required to enable all of them.  To engage in hands-on activities may not be available.


Similarly, learning by doing may not be appropriate where there are possible safety risks.


Teacher demonstration can introduce to specialized equipment and materials and show them how they are used.

During the demonstration, the learners should be involved in:

  • Making observations
  • Recording observations
  • Answering questions
  • Carrying out simple tasks
  • Asking questions


Planning a classroom demonstration careful planning will contribute to the success of classroom demonstration.

The teacher should consider the following:

  • Identify the intended learning outcomes of the demonstration so that these can be communicated to the students.
  • Consider the various steps involved in the demonstration listing the equipment and other material that you will need to collect together before the lesson.
  • Check whether you require teaching aids such a charts, pictures, posters and models to complement the demonstration.  The board may be used to highlight key words and important points.
  • Check the classroom seating arrangements provide your pupils with a clear view of the demonstration.
  • Rehearse the demonstration so that you are sure of the order in which to do things and can address any possible problems.
  • List the questions that you can ask pupils before during and after the demonstration to engage them and focus the attention.
  • Identify as many opportunities as possible to develop scientific enquiry.  Allow learners to predict what will happen, observe any perceptible changes, record their observations and draw their own conclusions.


A good classroom demonstration should capture pupils’ interest from the start, with an appropriate introduction to the topic reference to the intended learning outcomes and some exploratory questions to establish their current knowledge and understanding.


As you undertake the demonstration, you should explain what you are doing.It is important to carry out the demonstration neatly and systematically.







Discussion refers to the exchange of ideas between several people in the classroom environment; discussion is the best way of promoting conducive learning and convenient teaching, situation.


It refers to the method of instruction which give pupils an opportunity to express their views or opinions orally on certain issues.  One person speaks at a time, while others listen.


Discussion involves sharing ideas and experiences solving problems and promoting tolerance with understanding.


There are different forms of discussion that can be used in the classroom.


Kochhar (1985) identifies two major types of discussion which are formal and informal.


Informal discussions are governed by pre-determined set of rules and it includes debates, panels, symposia etc.


Formal discussions may involve


  • Whole group /class discussions
  • Small groups.


In the classroom discussions involve a free verbal interchange of ideas for all pupils as a whole.

Here the teacher is the leader who guides the discussion and asks questions.


Small group discussions are better than a whole class discussion.  It encourages more pupils to give their own views through open participation. Learners are divided into small groups of four, five or seven and given questions or task to discuss and then report back.


Each group should have a group leader who is instructed to control the discussion process and someone who can report back of what has been discussed.


The group seating arrangement should be in such a way those pupils are related and can hear, see each other well.

The teacher should identify the objectives of the lesson.

Discourage domination of the discussion by the outspoken members in the group.

  • Encourage shy children to contribute
  • Ensure pupils  stick to the topic


Advantages of Discussion Method


  • It teaches interpersonal skills such as understanding and communication.
  • It is child centered by providing an opportunity for pupils to learn from each other thus encouraging teamwork.
  • It promotes tolerance and helps pupils to understand there are many aspects or opinion to any one topic.
  • It also helps to develop leadership, speaking and listening skills.


Going on a science walk with children is an excellent way to inspire a love and appreciation for the nature world and also developing interest in science.


Learning should not be limited to the classroom and children should be taken for science walk in the local environment.


Through science walks children can easily learn about nature, weather, energy and have a better understanding of the environment.  During the science walk the teacher should:


  • Ensure the safety of the children
  • Direct pupils observations
  • Guide pupils activities
  • Ensure that pupils record their observations.
  • Encourage pupils to ask questions.
  • Ask probing question


Science walks can be taken to any area of learning value such as ponds, gardens, weather station, construction sites etc.




There is no substitute for seeing plants and animals in their native habitats if the teacher is to put into practice the principles of effective observation.There is a wide variety of places where the teacher can take pupils for learning purposes such as;

  • Ponds
  • Nature trail
  • Streams
  • Gardens
  • Parks
  • Industries
  • Museums
  • Garages
  • Construction sites
  • Airports
  • Weather stations and many other


Proper organization is needed if the pupils are to learn more on the field trip than they would in their own classroom.  The Head Teacher, school committee and parents must be assured before the teacher undertakes the trip.


The teacher is legally responsible for the safety of children under his/her care and so should caution them on all possible dangers and give the necessary precautions.


The role of the teacher is key, when using this method.



Find out and record the following


  • Essential preparations before the visit
  • The role of the teacher during the visit
  • Follow up work after the trip.




The lecture has been used.  Frequency in elementary and Secondary Schools, Colleges and Universities.  However with the current emphasis on “Inquiry Training” or discovery learning many educators consider lecturing outmoded for the following reasons:


  • The lecture dues not engage the learners in active learning
  • Knowledge taught through lectures is quickly forgotten.
  • Lectures do not adequately motivate the learners


Those who support the lecture method as an instructional technique argue that, it is not the technique itself, but rather its abuse, that is at fault.


A formal lecture is purely verbal; communication is basically one-way, from speaker to audience in an informal lecture, communication is two-way: from speaker to listener and from listener to speaker.


An informal lecture allows listeners to interrupt with questions or comments.  Such a lecture can also be enhanced by use of visual aid and audio-visual media.



A project means a piece of work carried out by an individual pupil or a group of pupils or a group of pupils on a specified topic. It may be a practical work e.g. construction of weather measuring instruments; mathematical, evaluative or research based project.The project should have well defined objectives so that a pupil will have something definite to aim at.




State five reasons that would make a teacher apply this method.



Drama and role play can be fun and used successfully in any area of the Curriculum.This method makes learning memorable encouraging co-operation and empathy.

The method helps to develop communication and language skills of the learners.

A role lay places the learner into a learning situation closely resembling the real live environment in which the desired knowledge and behavior is exhibited.

This method improves children’s social skills and their creativity in role play, the learners assume the roles of characters and pretend to perform the various tasks.



Highlight the role of the teacher when this method is used.




Included under this term is a wide variety of materials whose purpose is essentially to make the presentation more vivid and concrete.  Such materials are referred to as teaching aids.  However the term teaching/learning resources include the reference materials e.g. books used by the teacher in preparation for teaching.


Unplanned and indiscriminate use of teaching aids particulars audio-visual aids is to be discouraged.

In every instance the teacher must have a specific purpose which is to be achieved through the use of teaching aid.



This refer to all the materials used by teacher to make the learning experience more effective in the classroom and in the school in general

When being prepared and used the teacher should think in terms of how they will promote learning.

There are 2 types of resources:-

1)  References – these are the specific page as of give of given text book, magazine from which       the teacher/pupils obtain information about the topic.

2) Learning aids    – are objects or representations of objects which are used in the course of teaching /learning    to increase the no of senses used in learning.

Benefits of Learning Aids

  • Stimulate pupil’s interest
  • Capture pupils interest
  • Clarify abstract concepts by giving then concrete dimensions.
  • Provide variety in learning
  • Evoke responses from the pupils
  • Promote critical thinking
  • Improve the class environment by providing materials.
  • Show details of some objects through magnification or simplification.
  • Bring distant environment to the classroom.
  • Save teaching time
  • Give meaning to words
  • Stimulate imagination
  • Aid memory.




  • Realia, print, models, environment, apparatus, equipment, audio-visual, resources persons.

Realia: – These are real objects or specimens and can be plants or plant parts, animals or

animal produces and substances.

Realia can be obtained for use in the classroom through collecting during nature work of

or field trip; or practical work.  If specimens are collected they should be preserved and      labeled before storage.


  • Motivating
  • Provide direct experience
  • allow learners to use various senses in learning
  • Are available in large quantities and are easily obtained.


  • Some are too big to bring into the classroom
  • Some may scare pupils and make class control a problem.
  • Some are too small to be seen with naked eye.
  • Some are dangerous or may harm learners.



  • A specimen is a thing or part of a thing taken as a representative of its


  • Allow learners to observe and study some objects that they would not be able to see at close range on normal circumstances.
  • Specimens are not alive and can be stored.
  • They are portable and preservable and can be collected from far.
  • Can be used for long if well preserved.




  • Are not alive and active like real things
  • Easily damaged if not well handled
  • Preservatives are used and can have bad odour.


A model is used in the absence of real objects or specimens, when real objects is delicate, too big or too small.

  • To show internal parts of an organism without destroying the real objects.
  • A model is a recognizable representation of the real thing.
  • A model may be complete in every detail or simplified in detail that real things , some are

commercial, while others are made locally.


  • Is a three dimension object that gives feeling of depth and substance like real thing.
  • Gives feeling of presence of real thing
  • Can be handled
  • Can be used to enlarge or reduce object
  • Can be used to show interior structures of objects in details.
  • Can be used to represent very complex processes.


  • Can give wrong impression of real thing May be over simplified and misrepresent the real thing.



Involves taking pupils to areas in school or around school for learning.

Allows learners to interact with organisms/objects in the natural settings.

Apparatus and equipments

Are commercial or improvised items used during experiments, practical work or projects.

Apparatus include – burners, test tubes, beakers glass, thermometers.

Equipment e.g. fridge, cookers microscope etc.

Even in cases where commercial apparatus are available, the teacher/pupils can improvise to save on cost and to utilize locally available material.

Audi aids

Resources that target the use of ears during learning process e.g. radio, cassette, VCD players.

In Kenya the K.I.E broadcasts radio programs for different subjects and levels.

Teacher can also record or buy recorded cassettes or VCDs during lesson.

  • Audio aids enhances learning
  • They develop the skill of listening in the pupils.

Visual Aids

Learning areas which target the use of eyes during the learning process include, pictures,

photographs, charts, posters maps etc.


A poster is a visual combination of bold design and message.

  • Delivers message which should hold attention of passer by long enough to reinforce important message.


A learning resource that summarizes important information and idea through combination of drawings, words, symbols and pictures.


  • 2 dimensional representation of objects
  • Pictures are obtained from newspapers calendars, magazines etc.
  • Photographs are developed from photographic film used in cameras.
  • When used during learning choose those that are relevant to the topic,

appropriate for age of learners, are bold, clear and accurate, have straight forward

message and are big enough.

Audio-Visual Aids

Learning areas  that appeal to both eyes and ears during learning process.

  • Include television, films and video shows
  • They combine sound and picture making learning more real.
  • They have movements and can be used to show a process.
  • Create impression that view is watching something real due to three dimensional impacts.


  • Include textbooks, newspapers and magazine articles.
  • These resources contain pictures and illustration that enhance understanding, may

contain current information relevant to the  learners and provide information that learners has difficulties expressing in words.

During learning a teacher  can use them to refer to pupils to obtain information or to display

pictures or diagrams.

When text books are used to give exercises, they engage pupils during the lesson.


Resource Person

Involves inviting guest to provide some useful information to learners.

Resource persons can be:-

(i) Professionals

  • People who have knowledge and skill by virtue of training e.g. Doctor ,Nurse, engineer, Architect etc.
  • Give learners insight from experience at work and training
  • Used when teacher wants learners to obtain some technical details from expert.


Experience Group

  • Involves use of people with knowledge and skills by virtue of what they have gone through in life e.g. Cancer survivor, Accident survivor etc.


How to use a resource Persons

Preparation before the presentation:-

(i)  Discuss with resource person the following;

  • Objectives of topic
  • Scope
  • Language level of learners
  • Time available
  • Level of learners

(ii)  Inform the learners about topic of discussion.

During presentation;

  • Introduce guest
  • Note areas requiring clarification
  • Help learners to ask questions
  • Maintain class discipline
  • Summarize the main points learnt



  • Involve making something from whatever is available
  • Apparatus/Equipment can be improvised for doing experiment.


  • Improvised apparatus are easier to handle
  • Makes use of locally available materials
  • Develops many scientific skills and attitudes
  • Cheaper compared to commercial apparatus.
  • Can be used when commercial apparatus are not available.


Disadvantages of Improvisation

  • Time consuming in making
  • Improvised object may not resemble real apparatus.
  • Does not give accurate measurements
  • Some apparatus cannot be improvised
  • Materials to use in improvisation may not be available.




  • List five reasons why a science corner should be maintained in the classroom.
  • List ten items that are suitable for display in the science corner.







A scheme of work is the breakdown of the syllabus topic into teachable units to be covered in a given period of time such as a term or a year.It is therefore the teachers plan to cover the syllabus for a given subject.  A Scheme of Work is part of the teacher’s preparation for Teaching and Learning.



Why it is necessary to prepare a scheme of work?


  • It enables the teacher to cover the syllabus topics in a systematic and logical sequence.
  • It helps the teacher topics within the given time.
  • It helps the teacher to identify and prepare the teaching and learning resources.
  • It helps the teacher to project ahead for other schools programmes such as drama, sports and music.
  • It helps the teacher to prepare the teaching and learning activities and approaches to use.
  • It makes handing over and taking over from one teacher to another easier.



(i)  The Prevailing Weather Conditions

Some topics such as plants, light are best done when the weather conditions are favorable.  Certain observations are better done at certain times of the year.

The wise teacher will keep such ideas in mind when selecting what activities to do.


(ii)  Long Term Projects

Some units such as the weather require observations to be made for a few minutes daily over many weeks.  Teachers should select other units to be taught concurrently with these longer term projects and should scheme accordingly.


(iii)  Local Resources


Materials to teach many activities can be found in the local environment, teachers should plan in their schemes that such materials are collected for use well in advance.


(iv)  Children’s Interest

Teachers should develop their schemes of work with the interest of the pupils in mind.  It is not wise to scheme ten lessons for unit and continue to teach if children have become bored after the seventh lesson.Similarly if children are still productively involved at the end of a unit, there is no reason why the teacher should not extend his teaching for a few extra lessons.The teacher should also be prepared to interrupt the planned teaching for unexpected events that interest children.


(v)  The content and the scope of the syllabus should also be considered to ensure syllabus
coverage within the stipulated time.



The following are the basic component of a scheme of work.

  1. Week
  2. Lesson
  3. Topic/sub-topic
  4. Objectives
  5. Teaching activities
  6. Learning activities
  7. Teaching/Learning resources
  8. Assessment
  9. Remarks

Thus the scheme of work consists of nine columns, the SRE of each being determined by the content.

  1. Week

Each term consist of a specific number of weeks depending on the term dates provided by the Ministry of Education.  The teacher therefore is guided by the term dates and should plan for all the weeks.  These normally range from 11-14 weeks.  Adequate content should be identified from week on (1) to be taught from week one (1) to the last week, taking into account examinations, other co-curricular activities and national holidays.

  1. Lesson

The number of lessons taught per week, per subject is determined by the Kenya Institute of curriculum development.  In preparation, the scheme of work, the teacher should plan the teachable units in terms of each lesson.  e.g. is three lessons  are provided for in the time table, the teacher should prepare to teach the three lessons i.e. 1,2,3 every week.


  1. Topic/sub-topic

The topics for each class are indicated in the syllabus. The teacher should indicate the topic in capital letters and the sub-topic in small letters.  For accurate interpretation of the curriculum, the teacher should closely follow the syllabus.


  1. Preparing instructional objectives


The first step in both teaching and evaluation is that of determining the learning outcomes to be expected from classrooms instruction e.g. what should pupils be like at the end of the learning experience?


What knowledge and understanding should they possess?

What skills should they be able to display?

What interests and attitudes should they be able to display?

What specific changes are we striving for?

The intended learning outcomes are established by the instructional objectives.A clear description of the intended outcomes of instruction aids in :-

  1. Selecting relevant materials and methods of instructions
  2. In monitoring pupil learning progress.
  3. In selecting or constructing, appropriate evaluation procedures.
  4. Conveying instructional intent to other.
  5. Selecting appropriate teaching and learning activities.

The main purpose of classroom instruction is to help pupils achieve a set of intended learning outcomes.  These outcomes would typically include all desired pupil changes in the

  • Intellectual
  • Emotional and
  • Physical spheres.

The intended learning outcomes are expressed in terms of instructional objectives and stating them clearly in terms of desired learning outcomes can we provide direction to the teaching process.  Blooms Taxonomy of educational objectives divided objectives into three major areas.

  1. The cognitive domain is concerned with knowledge outcomes and intellectual abilities and skills.
  2. The affective domain which is concerned with attitudes, interests, appreciation and modes of adjustment.
  3. Psychomotor Domain is concerned with motor skills.

Each of these three domains is further divided into categories and sub-categories.

The major categories of the cognitive domain consist of the following levels of abilities in order of increasing complexity.

  • Knowledge
  • Comprehension
  • Application
  • Analysis
  • Synthesis
  • Evaluation
  1. Knowledge

Knowledge is defined as the remembering of previously learned material.This may involve the recall of a wide range of material, from special facts to complete theories, but all that is required is the bringing to mind of the appropriate information.Knowledge represents the lowest level of learning outcomes in the cognitive domain.

  1. Comprehension

Comprehension is defined as the ability to grasp the meaning of material.  This may be shown by translating material from one form to another, by interpreting material, explaining or summarizing and by estimating future trends.

  1. Application

Refer to the ability to use learning materials in new and concrete situations.  This may include the application of such things as rules, methods, concepts, principles, laws and theories.

  1. Analysis

Analysis refers to the ability to break down material into its component parts so that its organizational structure may be understood.  This may include the identification of the parts, analysis of the relationships between parts and recognition of the organizational principles involved.


  1. Synthesis

Synthesis refers to the ability to put parts together to form a new whole.  This may involve a plan of operations (research proposal). Synthesis stress creative behavior and formulation of new patterns or structures


Evaluation is concerned with the ability to judge the value of material, (statement, poem, research report for a give purpose.

The judgments are to be based on definite criteria e.g. organization and relevance.


Involves staidly the types of pupil performance to be expected (demonstrated) at the end of the teaching / learning experience.

NB:  What should the pupils be able to do by the end of the lesson that they could not do at the beginning?

This question should always be answered in terms of;

  • Knowledge
  • Scientific skills
  • Scientific attitudes

Thus a science lesson should have at least three objectives.


  1. Knowledge objective
  2. Skill objective
  3. Attitude objective


Verbs used should be specific i.e. indicate definite observable responses i.e. responses that can be seen and evaluated by an outside observer.The terms used should make it clear precisely what the pupils will do to demonstrate their understandably.Such vague terms as realize see know and believe describe internal states and are not observableunless expressed by different types of overt behavior.


Knowledge:  By the end of the lesson the learner should be able to:


– Describe



– Name

– Outline

– State

COMPREHENSION                                             APPLICATION

  • Distinguish                                        – Demonstrate
  • Estimate         – Predict
  • Explain                     – Show

– Solve

– Use

ANALYSIS                                                     SYNTHESIS    

  • differentiate – Device
  • distinguish – Design
  • Identity – Organize
  • Illustrate – Reorganize
  • Separate


  • Compare
  • Conclude
  • Criticize
  • Justify
  • Interpret

Acceptable instructional objectives must fulfill the following qualities;

  • Be specific
  • Measurable
  • Achievable
  • Realistic
  • Time bound

(5)  Teaching Activities

The desired pupil changes in terms of knowledge, skills and attitudes are brought about by          the planned teaching and learning activities.

In this particular column the teaching should indicate how he/she intend to engage the learners in the learning process in order to achieve the specified objectives e.g. if the knowledge objective indicates that learners should be able to define  the term energy; then as a teaching activity the teacher should plan to discuss and demonstrate the meaning of the term energy  thus the teacher systematically indicate all the activities that reflect the teacher’s role in the lesson from introduction to conclusion of the lesson.

(6)  Learning Activities

In this column the teacher should indicate specific ways in which the learners will participate in the lesson.

NB:  For every teaching activity there should be a correspondent.


For example if the teacher intends to discuss pupils observation after a practical activity then the

Corresponding learning activities would be;

  • Learners report their observations
  • Learners record observations

The teacher must ensure that the activities highlighted in this column are as systematic, clear and precise e.g.

  • Answering question on examples of simple machines
  • Observing and identifying simple machines
  • Recording a simple procedure on how light travels

N.B:  Both teaching and learning activities should develop and evaluate the types of pupil performance specified in the objectives.


For effective teaching and learning it is important that the teacher avail as many different


pes of teaching and learning resources as possible.  Under this title the teacher should indicate

  • Teaching Aids
  • References in terms of books, titles, relevant pages, author(s) and publisher.

The teacher must prepare suitable teaching aids in terms of numbers, quality and relevance to the sub-topic.


Assessment is a process of evaluation and measurement of the pupil’s attainment during and after a learning experience.

There is a wide range of methods that the teacher can use and the most appropriate should be selected.

  • Oral test /Questions
  • Written tests/exercises
  • Projects
  • Finished products
  • observing pupils while at work
  • Practical tests

In this column the teacher should record the feedback on whether

  1. Was the lesson taught?
  2. If not taught the reason
  3. When the lesson will be taught
  4. What were the pupils able to do in terms of the specified objectives

4.4       Preparation of a Sample Scheme of Work


Using the above guidelines and with the help of your subject tutor you will be expected to use the primary science syllabus to discuss and prepare a sample scheme of work.

4.5       Reasons for stating skill, knowledge and attitudinal objectives

As discussed earlier the main purpose of classroom instruction is to help pupils achieve a set of intended learning outcomes. These outcomes would typically include all desired pupil changes in the;

  1. Intellectual
  2. Emotional
  3. Physical spheres

Bloom’s taxonomy of educational objectives also divides objectives into three areas;

  1. The cognitive domain which is concerned with knowledge outcomes and intellectual abilities and skills.
  2. The affective domain concerned with attitudes, interests, appreciation and modes of adjustments.
  • Psychomotor domain which is concerned with motor skills to meet the requirements of the scientific approach to problem solving. Every science lesson should have the three types of objectives in order to enable the learners acquire
    1. The desired knowledge
    2. Develop the scientific problems solving skills
    3. Develop the necessary scientific attitudes

Example; By the end of the lesson the learner should be able to;

Knowledge Objectives

Give examples of soluble and insoluble solids

Skill Objectives

Classify solids into soluble and insoluble solids

Attitudinal Objectives

Develop further the attitude of curiosity as they investigate soluble and insoluble solids


List all the scientific skills and attitudes and use them to formulate suitable instructional objectives




A lesson plan is a systematic description of both the teaching and learning activities the teacher intends to cover in a particular lesson to cover in a particular lesson in line with the specified objectives and as per the scheme of work.

  1. The lesson plan enables the teacher to present the lesson in a systematic manner.
  2. Facilitates effective use of available time
  3. Enables the teacher to internalize the content to be taught
  4. Builds teachers confidence in terms of readiness to teach
  5. Lesson planning enhances the effectiveness of the teacher
  6. Enhances progressive coverage of the syllabus

A lesson plan provides an objective basis for assessment and self-evaluation of a teacher.

5.2       Main Components of a lesson Plan

The main components of a lesson plan consist of:

  1. Administrative details; class, roll, subject, date and time
  2. Topic- written in capital letters
  3. Sub- topic write in small letters
  4. Specific objectives e.g. by the end of the lesson the learner should be able to;
    1. Knowledge
    2. Skill
    3. Attitudinal
  5. Teaching/ learning resources
    1. Teaching aids (materials, apparatus, charts)
    2. References (indicate title, author, pages and publisher)


This is the systematic organization of the teaching and learning activities in terms of introduction development conclusion with an introduction of various steps and the time allocated.








Introduction 5 min Must realistically link new work with previous pupil  experience Focus pupils attention

-motivate pupils

II 5 min Discuss instructions and procedure to investigate solubility of different sounds Observe and record the procedure.
III  5 Min Involve learners in activities to  investigate

Solubility of solids

Mixing different solids with water e.g. sand, sugar
IV 5 min Discuss pupils observations and assist them to classify solids Report observations

Record soluble and insoluble solids.

V 5 min Give written exercise Do the written exercise
VI 5 min Use oral questions to review the main lesson Answer oral questions on solubility of solids.






New words Soluble and insoluble solids

material apparatus
















The teacher should reflect on the lesson conducted with the open mind and write comments on the positive and weakness of the lesson e.g. the lesson was successful and learners conducted all the planned activities.

  • Preparation of a sample lesson plan

Using the lesson plan guidelines given above, prepare a sample lesson plan drawn from your science scheme of work prepared earlier for a specified class.



Measurement gives numerical value on an achievement of an attribute in a person. It can be done quantitatively by giving numerical values e.g 60%. It can also be done using qualitative description e.g good, excellent, weak.


When measuring the achievement of instructional objective various measurements are used. This includes continuous assessment tests, examination and standardized tests. The word assessment is at times used for measurement. In the teaching and learning processes assessment would include preparing the tests, giving out the tests, marking and awarding marks.


Evaluation involves marking a value judgment e.g.  How good the learner is such a learner pass or fail? What is the quality of the score? Evaluation can use assessment scores to make judgments e.g.

Scores                  Grades (helps give a value judgment)

90-100                         A

85-89                           A-

80-84                           B+

75-79                           B

70-74                           B-

65-69                           C+

60-64                           C

55-59                           C-

50-54                           D+

45-49                           D

40-44                           D-

0-39                             E


This can help us answer the question “How good is a learner who gets 60%?”

Purpose of Assessing Learners


  1. To find out whether the objectives set at the beginning of the lesson have been achieved.
  2. Find out whether learners have understood what has been taught.
  3. To evaluate the effectiveness on teaching methods used.
  4. To motivate learners to study.
  5. To determine learners abilities for the purpose of grouping.
  6. To identify weak learners who may require special attention or remedial work.
  7. To find out the progress of the learners so as to give this information to the parents and guardians.


Assessment can either be done formally or informally.

  1. Formal assessment
  1. Done using written tests and projects.
  1. Informal assessment

Done using oral questions as one teaches, it gives immediate feed-back.

  1. Formative assessment.

Assessment done to provide information that would be used to enhance the learning of learners involved. It gives the teacher feed-back no the progress of learners and is done frequently within a term. It is planned as the teacher plans the lesson. It can be done formally or informally.

  1. Summative assessment

Assessment carried out at the end of a course (terminal) for the purpose of awarding certificates and accountability. It is used to show whether the objectives of the course have been achieved. It is usually done formally


  1. Diagnostic assessment

Assessment carried out to diagnose (find out/ identify) learners specific needs. This provides the teacher with information that can be used to take the necessary corrective measures in teaching or planning what to teach those learners. This may be done formally or informally

Methods of Assessment
There are three areas one may want to assess in a learner:

  1. Acquisition of knowledge by learner
  2. Skills acquired or developed
  3. Attitudes developed

Some of the methods that can be used are (Methods of evaluation)


  1. Observation

This involves the teacher making direct observation as the learner performs a practical tasks or activity. It is a form of continuous assessments to help teachers to diagnose areas where learners need guidance.

  • This method can be used to evaluate some skills in particular those that relate to practical activities i.e. manipulative skills e.g. designing and setting up an experiment, measurement, controlling of variables etc.


  • A good and standard criterion to award marks or grades needs to be made otherwise, the assessment would be subjective e.g.


-Using the correct procedure

-Using appropriate experimental techniques.

-Completion of the activity

-Organization of the materials


This is the method that is used to evaluate attitudes.




  1. Oral questions


  • Involves teacher asking questions orally and the learners’ answers oral as the lesson progresses.
  • This method can be used to develop and assess communication skills in a learner.
  • It also gives the teacher an immediate feed-back.
  • In a class having hearing and hearing impaired (challenged) learners this method would disadvantage the hearing impaired learners. It would be necessary to also write the question asked on the chalk board or have a sign language interpreter to sign for hearing impaired learners


  1. Written tests
  • Involves giving written questions to be answered by learners
  • It is important for the teacher to mark the questions and then do corrections.

Written questions may be in the form of essay or objective questions.


  1. Essay questions

Involves giving a question in which learners’ answer is in their own words.

They may require learners to write long answers or they may be structured such that learners write short answers.

Structured essay questions are more objective I scoring than long answer essay questions which are subjective in scoring.


Advantages of essay questions

  1. Relatively easy to set
  2. Learners are given the opportunity to express themselves and thus explain their answers.
  3. Can be used to test for creativity and originality.
  4. Develops communication skills in a learner.




Disadvantages of essay tests

  1. Difficult to mark
  2. Difficult to have objective scoring
  3. Disadvantages learners who have communication problems. Therefore, it is not appropriate for learners who are starting to learn like those in lower primary.
  4. Tests a small area of content covered by learners


  1. Objective questions

There are four types:

  1. Multiple choice questions
  2. Matching type questions
  3. Completion type questions
  4. True/ False questions
  1. Multiple choice questions

A scientific statement forms the stem. It is usually followed by four closely related responses. The correct response is called the key and the incorrect responses are called the distracters. The stem should be clear and not too long. There should be only one key.

Setting multiple choice questions


Which is the correct name of the female part of a flower?

  1. Stigma           B)  ovary          C)  stamen      D)  pistil
  2. Matching type

A column of items is given and a column of responses to match. The number of items and responses are different; one then matches the items with the correct responses


            Animals                       Name of group

Cow                             Reptile

Frog                            Mammal

Lizard                         Amphibians

Bat                              Birds


  • Completion type

Sometimes referred to as “filling in blanks” questions. A blank space is left within or tats the end of a scientific statement. One is required to fill the blank with the correct word or words.


A sweet potato tuber is an example of a ______________tuber.(stem,  root)

  1. True/False questions

A scientific statement is given and at the end you put the words TRUE/FALSE

one decides whether the given statement is true/ false


A chameleon is a reptile. True or False.

Setting multiple choice questions

  1. Write the stem first
  • It should be clear not ambiguous
  • Use language level appropriate to the learners being tested.
  • Should be precise (not have irrelevant information)
  • Avoid negatively stated points
  1. Write the key (correct response)
  • Ensure there is no clue in the stem
  • The position of the key should vary from one question to another


  1. Read the stem and the key


  • To ensure the key is correct for the stem


  1. Write the distracters


  • Should as closely to the key as possible
  • Distracters and the key should be of the same length


  1. Read the stem and the responses to ensure there only one key


Correction for guessing

Assuming that every long item is because of guessing the formulas below can be used to penalize learners for this guessing. (However note such wring items may also be as a result of  having wrong information)


  1. True or False questions


S = R – W

S = final score            R = number of items right      W = number of items wrong


Length Should be brief as too much information tends to confuse a candidate


Practical test

They have questions which require one to carry out a practical task in order to answer the questions. Such questions may involve setting up experiments an experiments and making observations, construction of improvised apparatus etc. such tasks enable examiner evaluate manipulative skills in a learner as well as the scientific attitudes


e.g. Design and set up an experiment that can be used to investigate whether water is necessary for rusting to take place

There should be clear guide-line in assessing practical work   e.g.


  • Following instructions (procedure) correctly
  • Way of handling apparatus
  • Ability to control variables
  • Using suitable ways to record information
  • Drawing logical conclusions
  • Quality of product made
  • Make correct observations



Consider the following when developing a test

  1. Objectives of a topic and the content taught
  2. Amount of subject matter covered per topic. Questions should correspond to the size of content area in a topic.
  • Identify areas given more emphasis by the syllabus and allocate questions accordingly
  1. Duration of the test

This will be determined by a number of questions

Number of questions testing different levels. Levels in the Blooms Taxonomy can be used as a guide.Making a table of specification or specification grid can help. It shows topic tested and number of questions in each of the levels.





Knowledge Comprehension Application Analysis Synthesis Evaluation TOTAL
Properties of matter 3 1 1 1 1 1 8
Animals 4 0 2 1 1 0 8
Plants 2 3 2 1 0 0 8
Weather 1 0 4 0 0 0 5
Water 3 1 1 0 0 0 5
Human body 5 1 1 1 0 0 8
Soil 2 1 1 1 0 0 5
Energy 1 0 2 0 0 0 3
TOTAL 21 7 14 5 2 1 50

Questions can be classified according to the level of mental ability they test

  1. Recall (knowledge) questions
  2. Comprehension questions
  3. Application questions
  4. Analysis questions
  5. Synthesis questions
  6. Evaluation questions

The above classification is based on Blooms taxonomy

Bloom’s Taxonomy

This taxonomy was developed by Benjamin Bloom. It gives various cognitive levels which a teacher can engage a learner through questioning. It is important for the teacher to utilize both lower order questions in the knowledge and comprehension levels and also develop learner’s reasoning abilities by asking them questions in the higher order of Application, Analysis, Synthesis and Evaluation.


Knowledge Recalling of ideas, principles, places, events, Names, observations made, procedures or information as it was learnt

It requires one to have memorized information required.

Who , Name,  List down,

Define, State, When, Where

Comprehension -Understanding information or data or facts based on prior learning

-Organizing ideas

-Grasping the meaning of terms

-Translating from one medium to another

-Predicting consequences given the background








Application -Problem solving using the information or principles learnt

-Use of facts, rules and principles in new situations

-Apply information learnt to produce some result

-Relating practical use with principles learnt

-Use  information learnt to choose or explain why some materials are better than others in some uses e.g. constructions

-Transfer of knowledge to solve new situations.

Use …

Solve …

Apply …

Examine …

Classify …



Construct …

Show …


Relate …

Analysis -Breaking down / subdividing/ separating a whole into its component parts to identify any patterns

-Comparing and contrasting

-To identify motives

–        Looking for similarities and differences


Classify …

Select …

Compare and contrast

Explain why …

Distinguish …

Separate …

Synthesis -Integrate/ combine parts to form a whole

-Combine ideas to form a plan or proposal

-To form a prediction or inference

-Draw a collusion from given facts

-Design an experiment

Create …


Make a hypothesis…

Draw a conclusion…

Make an inference…

Develop a plan…

Evaluation -Make a judgment/ decision using specific criteria or standard

-Make  a critique

-Assess performances

-Prioritize items

-Make choices after presentations

Do you agree…



What do you think about…

Is there a better solution to…

Examples of questions from the various levels

  1. Knowledge
  2. Kamau was sent to the shop to buy sugar. On the way from the shop the sugar fell and mixed with sand. Which of the ways below would be used to recover the sugar?
  3. Dissolve in water, Stir, Evaporate, Filter.
  4. Filter, Dissolve in water, Stir, Evaporate
  5. Stir, Dissolve in water, Filter, Evaporate
  6. Dissolve in water, Stir, Filter, Evaporate


  1. One of the following sources of energy is renewable. Which one is it?


  1. Biogas from cow-dung
  2. Kerosene
  3. Coal
  4. Cooking gas from crude oil
  5. Comprehension
  • It tests understanding of facts or principles
  • It involves:

-Understanding information or concepts learnt

-ability to explain those ideas in our own words or identify those ideas when stated in different words. Interpretation of data and extrapolation is tested under comprehension

  • Requires learners to translate, interpret, explain, describe, summarize and extrapolate
  1. The diagram below show reproductive parts of a flowering plant



(diagram of a reproductive part of a plant)


  1. Which parts receive the pollen grains?


A:  X               B:  Y               C:  W              D:  Z


  1. the diagram below shows one form of dispersal



The seeds from this plant are dispersed by

A:  Wind         B:  Water        C:  Explosive mechanism                  D:  Animals


The graph below shows the increase iof antelopes in a area


Which year had the highest number of antelopes?


A:  1986          B:  1986          1990                19928

  1. Application
  • Involves facts or principles to solve problems
  • Application question usually take one of the following forms
  • Conditions are given and the resulting effects, one is then required to  give the underlying principle
  • The principle is given with the appropriate conditions. One is required to give the results
  • The principle is given together with results. One is then required to give the conditions.

Application questions will involve the use of logic or reasoning


  1. Adila cut his hands while peeling potatoes. The blood that spurt from the finger was dark. This shows that Adila has cut a
  2. vein    B)  artery        C)  capillary    D)  blood
  3. which of the materials given below would be the most suitable for making a handle of a frying pan?
  4. Iron B) Copper       C) Plastic        D) Aluminum
  5. The reason why fish is able to move easily in water is because
  6. It has fins
  7. It has hard scales
  8. It is streamlined
  9. It has gills


Involves breaking down an idea into small parts and then examining those parts to determine their relations and significance.It may involve deductive and inductive reasoning before giving an answer.

Requires learner to connect, relate, differentiate, classify, arrange, check, group, distinguish, organize, categorize, detect, detect, infer.


Which of the experiments shown below would be used to show that carbon?










Worms are parasites that are in our bodies.  They get nutrients from the body.  Poor hygiene was the chances of worm infestation.

Roundworm (Askaris)

  • They are usually 20-30cm long
  • They are pink or white in colour
  • They are spread from faeces-to-mouth as a result of poor cleanliness
  • The eggs pass from one person’s stool to another person’s mouth.

Effect on Health

  • Once swallowed the young worms hatch and enter the blood stream.  This may cause general itching.
  • The young worms travel to the lungs, causing, causing a dry cough or preumonia with coughing of blood.
  • The young worms are coughed up, swallowed and reach the intestines where they grow to full size.
  • Many round worms in the intestines may cause discomforts, indigestion and weakness.
  • Children with many round worms often have very large swollen bellies.
  • Sometimes they may cause asthma, fits or blockage of the gut.
  • When a child has fever the worms come out in stool or crawl into the airway causing gagging.


  • Use latrines
  • Wash hands before eating or handling food.
  • Protect food from flies
  • Follow guidelines of cleanliness


  • They may be 1 cm long and red in colour
  • They cannot be seen in the faeces.
  • A stool analysis is needed to prove their presence

How Hookworms Spread

  • The baby hookworms enter a person’s bare feet,  this can cause itching.
  • In a few days they reach the lungs through the bloodstream.  This may cause a dry cough.
  • The person coughs up the young worms and swallows them.
  • A few days later the person may have diarrhea or a stomachache.
  • The hookworms attach themselves to the wall of the gut.  Many worms can cause weakness and severe anemia.
  • The hookworm eggs leave the body in the person’s stool. The egg hatch on moist soil and back to step 1 – 6.


  • Use latrines
  • Wear shoes


  • In the intestines tape worms grow several metres long
  • They are small, flat, white pieces (segment) found in the faeces about 1 cm long.

How it Spreads

  • People get tapeworm from eating porkmeat, beef or other meat that is not well cooked.
  1. When a person eats poorly cooked meat the cysts become tapeworms in the intestines.
  2. The cysts may cause headache, fits or death.
  3. The egg enters the person’s mouth from his faeces
  4. Pig or cow eats the egg in the man’s stool.
  5. The worm eggs the cow or pig has eaten forms cysts in the meat and again this goes back to
    Step 1 – the person eats poorly cooked meat.

Effects on Health

  • Tapeworms in the intestines may cause mild stomachache
  • The greatest danger exists when cysts get into a person’s brain.  This happens when the egg passes from his stool to his mouth.


  • Eat meat that is properly cooked especially pork, ensuring that no parts at the centre are raw.
  • Wash hands after handling dogs.
  • Follow guidelines on cleanliness.

Common Communicable Diseases


These are easily passed from one person to another through air, physical contact and sharing unclean common user facilities:-

  • Through air, coughs, sneezes – airborne
  • Vectors – they suck blood – vector borne diseases – contagious diseases
  • Physical contact –skin of unhealthy person – sharing of personal items.
  • Water – human faeces or urine – waterborne.

Tuberculosis (T.B)

Tuberculosis of the lung is a chronic (long-lasting) contagious (easily spread) disease that anyone can get.

  • It strikes person between 15 – 35 years especially those who have Aids, or who are weak, poorly nourished or live with someone who has T.B.
  • T.B. is curable.


Frequent Signs


  • Chronic cough often worse just after waking up.
  • Mild fever in the afternoon and sweating at night.
  • Pain in the chest upper back.
  • Chronic loss of weight and increasing weakness.


Serious/advanced Signs


  • Coughing up blood
  • Pale, waxy skin
  • Hoarse voice


In Children


  • Steady loss of weight
  • Frequent fever
  • Light skin colour
  • Swelling in the neck (lymph glands) or the belly


Tuberculosis is usually only in the lungs, but can affect any part of the body.

  • It may cause menegitis to children
  • It may also cause skin problems e.g. tumors that disfigure, chronic patchesof sores, skin ulcers or big warts.



To Check For Tuberculosis (T.B)


  • Get a skin test. , take an ex-ray and examine sputum.
  • To cure Tuberculosis takes from 6 months up to one year.


How To Manage Tuberclulosis (T.B)


  • Eat foods rich in energy, proteins and vitanmins
  • Rest is important
  • Tuberculosis is very contagious.  People who live with infected persons can catch the disease.  Therefore:
  • The whole family should be tested for Tuberculosis
  • Children should be vaccinated against Tuberculosis
  • Infected person should sleep separately
  • One should cover mouth when coughing
  • Avoid spitting anywhere
  • Watch for weight loss and other signs of T.B. among the members of the family.




This is the infection of the blood that causes chills and high fever.


  • It is spread by mosquitoes, which suck up the malaria parasites in the blood of an infected person and injects it into the next bite.




The attack has three stages


  • It begins with chills and often headaches
  • The person shivers and shakes
  • Chills are followed by fever after 400 c or more
  • The person is weak, flushed skin and at times delicious.  Fever may last several hours.
  • Finally the person begins to sweat and temperature goes down.  After an attack the person feels weak but may feel more or less okay.




  • Malaria will cause fever every 2 – 3 days depending on the kind of Malaria.  It is important to have a blood test to check for malaria parasites.
  • Chronic malaria causes enlarged spleen and anemia
  • In children anemia and paleness can begin in a day or two.
  • When malaria affects the brain it is called cerebral malaria.  Fits may be followed by periods of unconsciousness.




  • It occurs often in hot rainy weather/season.
  • Avoid mosquitoes – sleep in mosquito nets.
  • Co-operate with malaria control workers when they spray around homes.
  • People should go for testing when they suspect to have malaria and get to avoid spreading to others.
  • Destroy mosquitoes and their young ones. Clear pods, pits, old cans or broken pots that collect water, drain or put paraffin oil on pools or marshes where mosquitoes breed.
  • Malaria can be prevented or reduced by talking anti-malaria medicines on a regular schedule.


Skin problems are caused by

  • Diseases or irritations
  • Could be signs of diseases that affect the whole body e.g. measles, pellagra.
  • Could be signs of serious diseases e.g. Tuberculosis, syphilis or leprosy.

(a)  Scabies 

This is common in children.  It causes itchy little bumps that appear all over the body.

Most common:-

  • Between the fingers
  • On the wrist
  • Around the waist
  • On the genitals
  • Between toes

Causes of Scabies

It is caused by small insects similar to ticks or jiggers.

How it spreads

  • It is spread by touching affected skin or clothes or beddings
  • Scratching can cause infection, producing sores with pus and swollen lymph nodes or fever.


  • Personal cleanliness is important.  Change clothes regularly.
  • Cur finger nails very short to reduce spreading and infection.
  • Wash all clothing and beddings or boil them and hang in the sun.
  • Wash the whole body vigorously with soap, towel and hot water.


(b)  Ringworms (Tinea-Fungus Infection)


Fungus infection may appear on any part of the body but occurs mostly on:-


  • Scalp (tinea)
  • Parts without hair (ringworm)
  • Between the legs (jock itch)


Most fungus infections grow in the form of ring.  They often itch.  Ringworm of the head can produce round patches with scales and loss of hair.


  • Fingers and toe nails infected with the fungus become rough and thick.




  • Wash the infected part every day with soap and water keep the affected area dry and exposed to the air or sunlight.  Change underwear and socks often.
  • Keep the affected are dry and exposed to the air or sunlight.  Change underwear and socks often.


Prevention of fungus infections


All fungus infections ate contagious


  • Do not let a child with fungus infection sleep with others.
  • Do not allow different children to share personal effects
  • Treat an infected child at once.



(a)  Cholera


  • Cholera often comes in epidemics (striking many people at once)and is usually worse in older children and adults.
  • Severe dehydration can develop quickly especially if there is vomiting.
  • It is vital to report to health facility.




  • Food and drink may be contaminated by bacteria
  • If faeces of a person suffering from intestinal disease (cholera) are deposited in/near water source, these are likely to be present in the water.
  • Disease bacteria may get into food when washed with contaminated water or deposited by flies.
  • Unwashed hands may be contaminated and bacteria is transferred during food handling.




  • Drinking water should be treated
  • Wash hands after visiting lavatory.
  • Observe personal and food hygiene.


(b)  Typhoid


  • It is an infection of the gut that affects the entire body.
  • It is spread from faeces –to-mouth in contaminated food and water and comes in epidemics.




1st Week


  • It begins like a cold or flu.
  • The headache, sore throat and a dry cough
  • Fever goes up and down and may reach 400 C
  • Slow pulse
  • There may be vomiting, diarrhea or constipation



2nd Week


  • High fever, slow pulse
  • Trebling
  • Spots may appear on the body
  • Delirium (not thinking properly)
  • Weakness, weight loss and dehydration




Seek medical help.




  • Avoid contamination of water and food by human faeces.
  • Use pit latrines which are a safe distance from sources of water
  • Causes of typhoid often appear after floods. Care must be taken with cleanliness.
  • Take clean drinking water.
  • To avoid spread persons with the disease should stay in a separate room.
  • After recovery some people still carry the disease and may spread to others without affecting themselves.


(c)  Bilharzias


There are three species of bilharzias worms or flukes called schistosomiasis.  They are 1 – 2 cm long and live in the veins of the bladder, large or small instestine.


  • Bilharzia is caused by the damaged and inflammation caused by the escape of the eggs from the infected organs to the outside world.
  • Eggs are laid in the veins where the worms are, then move through the wall of the bladder or instestine causing inflammation, pain and bleeding.


How Blood Flukes Spread


  • Infected person urinates or defecates in water.
  • Urine or faeces has worm eggs it.
  • Worm eggs hatch and go into snails.
  • Young worms leave snail and go into another person.
  • In this way someone who washes or swims in water where an infected person has urinated or defecated also becomes infected.




  • Any person who has blood in his urine or stools should have a sample of it tested for fluke eggs.
  • Common sign is blood in urine (bloody diarrhea)
  • Pain in the lower belly and between legs and worse at the end of urinating, low fever, weakness and itching.
  • After months or years the kidneys or liver may be badly damaged this may cause death.




Blood flukes are not directly from person to person.  Part of their life must be inside a certain kind of small water snail.


  • Co-operate with programmes to kill nails and treated infected persons should prevent schistosmiasis.
  • Everyone should learn to use latrines.


(d)  Amoebiasis


Amoeba cannot be seen naked eyes.




The stools of infected persons contains millions of these parasites.  Because of poor sanitation they get into the source of drinking water or into food and other people become infected.




Many healthy people have amoebas without getting sick.


  • Amoeba are a common cause of severe diarrhea or dysentery (diarrhea with blood)
  • It is already in persons already weakened by other sickness or poor nutrition.
  • On rare cases it may cause painful abscess in the liver.


Amoebic Dysentry Will Cause


  • Diarrhea that comes and goes, may alternate with constipation.
  • Cramps in the belly and a need for frequent bowel movement. At times mucus may come


  • Many loose (not watery) stools with a lot of mucus stained with blood
  • There is no fever.




Sometimes bloody diarrhea has other causes.  To be sure of the cause a stool analysis is vital.


Sometimes amoebas get into the liver and form an abscess (a pocket of pus)


  • This causes tenderness or pain in the right upper belly
  • Pain may extend to the chest (right side) and worse when a person walks.
  • If a person with these signs begins to cough up brown liquid, an amoebic abscess is draining into his lungs.



  • Seek medical attention.
  • Have a stool analysis.




  • Make use of latrines
  • Protect sources of drinking water.
  • Eat well and avoid fatigue and drunkness.
  • Follow cleanliness guidelines





These infections usually transmitted through sexual intercourse or contact.


(a)  Gonorrhea and Chlamydia


These two infections are spread by sexual contact and have the same early signs


  • Often a person has both gonorrhea and Chlamydia at the same time and has to be treated for both.


Signs in Men


  • Pain and difficulty with urination.
  • Drops of pus from the penis
  • Sometimes painful swellings of the testicles.


After Weeks Or Months


  • Painful swelling in one or both knees, ankles or wrists
  • Rash or sores all over the body.
  • He may become sterile (cannot sire children)


Signs in Women


  • At first there are no symptoms
  • She may feel a little pain when urinating or slight vaginal discharge.



After Weeks Or Months


  • Pain in the lower belly (pelvic inflammation)
  • Menstrual problems
  • She may become sterile
  • She may experience urinary problems


In men the first signs begin 2 – 5 days after sexual contact with an infected person.


In women signs may not show up for weeks or months.




Seek medical help.




A person who does not show signs can pass the disease to someone else starting a few days after infection.


  • A woman with gonorrhea or Chlamydia has fever and pain in the lower belly may have pelvic inflammatory disease.
  • Anyone who has had sex with person infected with gonorrhea or Chlamydia should be treated (wives or infected men).  If the wife is not treated she will infect the man again.
  • Protect the eyes of new born baby from gonorrhea and Chlamydia which may cause blindness.
  • Persons with gonorrhea and Chlamydia may have syphilis without knowing it.
  • Get full treatment for syphilis to prevent the first signs (but not to cure the disease).






  • Be careful with whom to have sex.  Avoid contact with many persons (have one partner)
  • Use condoms.  This helps to prevent STI’s but does not assure complete protection.
  • Get treatment right away to avoid infecting other persons.
  • Tell your partner to get treatment.


(b)  Syphilis


This is a common and dangerous disease that is spread by sexual contact.



The first sign is a sore called chancre and appears 2 – 5 weeks after sexual contact.


  • The chancre looks like a pimple, a blister or open sore
  • It appears in the genital area (or less common on lips, fingers anus or mouth)
  • The sore is full of germs which are easily passed on to another person.
  • The sore is painless, if inside the vagina a woman may not know and can infect others.
  • The sore lasts a few days and goes away without treatment, but the disease continues spreading through the body.
  • Weeks or months later there may be sore throat, mild fever, mouth sores or swollen joints or the following signs may appear on the skin:-


  • A painful rash or pimples all over the body
  • Ring shaped patches on the body
  • An itchy rash on the hands and feet.




  • All these signs go away by themselves, but the disease continues to spread.
  • Without treatment the disease can invade any parts of the body causing heart disease, paralysis, insanity among many other diseases.




  • Get medical help when you see a strange rash or skin condition showing up days or weeks after a pimple or sore appears on the genitals.




Same as for gonorrhea.


(c)  Candidiasis


Otherwise known as thrush or moniliasis


  • Candidiasis is caused by a fungal producing a thick white discharge
  • It is more common in women than in men , usually affecting the vagina but also other  areas of mucus membrane notably those inside the mouth.
  • The infection may be spread by sexual intercourse, but other clinical conditions may encourage the fungal growth.  These include the use of oral contraceptives, the hormonal changes associated with pregnancy and diabetes mellitus.
  • Accompanying the discharge there may be itching and irritation of the infected area, and discomfort when passing urine.
  • In men infection may cause inflammation to the head of the penis.  If the infection is in the mouth, sore raised creamy-yellow patches will be present in the mucus lining.



  • The diagnosis is confirmed by laboratory analysis of the discharge
  • Treatment takes the form of anti-fungal preparations supplied tablets, vaginal suppositories or creams.
  • Change of oral contraceptives (where this is a causative factor)


(d)  Herpes


  • One of the many different herpes viruses, genital herpes is caused by the herpes simplex virus and produces after about a week, a sore burning sensation, itching and small blisters scattered around the genital area.
  • The blisters open and leave small ulcers which may take as long as three weeks to heal.
  • A person with herpes virus may feel generally unwell and may also have a fever and a headache.



  • Currently there is no cure for genital herpes, but early diagnosis and palliative treatment with anti-viral drugs will help to reduce the symptoms and the severity of the condition.
  • Pain killers and other soothing measures to be applied to the blisters/ulcers.
  • There may be future flare-ups of the above symptoms, but the effect can be minimized by ongoing anti-viral treatment.






This refers to the situation when the Human Immunodeficiency virus infects a human person and affects the immune system causing a collection of diseases that make the syndrome – Aids.




HIV transmission is the passing on of the virus from one infected person to another who may or may not be infected.


  1. Through sexual intercourse with an infected person. About 80% cases occur as a result of
    sexual intercourse.
  2. Blood or blood products or contact. About 10% cases are known to occur through blood
    transfusion or use of blood product and having contact with blood.


For Example:


  • Through transfusion
  • Use of contaminated needles and syringes
  • Sharing of circumcision knives.


  1. Mother to child transmission. This causes a considerable number of cases of HIV.  For


  • During pregnancy HIV may be transmitted across the placenta to the foetus.
  • During delivery /at birth and the risk is higher with about 60-70%, because HIV may be transmitted through the mother’s blood.
  • During breastfeeding.
  • Through the use of contaminated body piercing objects.  these include needles, syringes, blades, knives, surgical instruments. If the mentioned objects are used on infected persons then HIV will be easily transmitted to another person.


(b)  Stages of Development


There are six stages of HIV progression.  These are:-


  • HIV infection stage
  • Window period
  • Sero conversion sero (+ve or –ve)
  • A symptomatic HIV infection.
  • Related illnesses/opportunities infections
  • Aids stage (full blown)


Stage I


When first infected by the virus a person looks normal and healthy and is unaware of the fact.  However, the person still carries the virus and can infect other people.


Stage II


This is the period at which the body begins to develop antibodies to fight the virus.  The period paves the way for window period – which refers to the period acquiring the virus and the time a person tests positive.  A person can infect other people during the window period.

Stage III

Seroconversion stage is the period when an infected person changes from a negative status to a positive status.

Stage IV

This is the symptomatic HIV infection period.  During this stage a person has no symptoms of Aids but the virus is slowly multiplying in the white blood cells destroying the body’s immunity status.  The virus suppresses the person’s immunity exposing him to opportunistic infections displaying a symptomatic HIV infection.


Stage V

This is the opportunistic stage whereby the disease such as Tuberculosis, herpes zoster and candiasis are known to take advantage of the body’s lowest immunity.  These illnesses strike the body with the purpose of establishing themselves, a condition that leads to AIDS.


Stage VI

AIDS stage.  This is the period that surfaces as a result of weakness in body’s immune system.  It is the final period HIV virus.



(c)  Counseling and Testing


What is VCT?


  • It stands for voluntary Counseling and Testing.  It refers to the process by which a person finds out whether or not he/she is infected with HIV, the virus that causes AIDS.




Refers to a helping relationship established between a healthcare provider and a visiting client to a VCT centre.


Who Should Receive VCT?


  1. Anyone serious about behaviour change
  2. Those with more than one sexual partner.
  3. Those diagnosed with STD or TB
  4. Anyone 18 years and above
  5. Couples before starting a relationship, before marriage and for pregnancy planning.
  6. Mature minors (15-18 years) who have already engaged in risky behavior.




Children under 15 years should be served only with parental consent and only if there is a clear benefit to the child.


Basic Steps Involved in Counseling for HIV


  1. HIV/AIDs information
  2. Pre-testing and test decision Counseling
  3. Post-test Counseling
  4. Plans for reducing risky behavior


What is Pre-test Counseling?


This is the counseling done before the HIV test.  It involves assessing one risk of contracting HIV, discussion on the test and expected results, thinking through the possible results and discussing basic HIV facts as well as risk reduction methods.


What is Post-Test Counseling?


This is done after the patient receives his/her results.  Other issues discussed at this point are positive living, risk reduction, planning, window period, partner notification and additional counseling sessions for both positive and negative individuals.


Benefit of Counseling and Testing to Individuals


  1. It empowers the uninfected person to protect himself/herself from HIV.
  2. It assists infected persons to protect others from being infected and live positively.
  3. it offers opportunities for early treatment of HIV and HIV associated infections.
  4. For couples and families if offers/supports safer relationships thereby enhancing faithfulness.
  5. It encourages family planning and treatment to help prevent mother to child transmission of


  1. It allows couples and families to plan for the future.


(d)  Myths and Misconceptions


There are several myths and misconceptions about HIV transmission.  One does not get HIV from hugging, sharing toilets, sharing utensils, shaking hands, sharing clothes, living in the same house, mosquito bites, kissing, but this might be risky if one has bleeding gums, wounds or when saliva is mixed with blood.


Development and Disease Progression


The virus is spread from one infected person to another person following exchange of body fluis that contain the virus.


(a)What are CD4+Lymphocytes?


They are types of white blood cells which are important in the body’s immunity.


(b)  Where are the CD4+Lymphocytes Found?


They are found in blood and body tissues where they form a front line defence against invading germs.  There are parts of the body which always have a high concentration of CD4+Lymphocytes.  These are:-


  • The vagina
  • Foreskin of the penis (Prepuce)
  • Alimentary tract from mouth to anus.
  • Sites of injury e.g.wounds


(c)  How does the body react to the HIV Virus?


  • The body reacts by producing anti-bodies to fight the HIV virus.


(d)  How does the virus affect the body and Cause Disease?


  • The virus attaches to white blood cells in particular the CD4+Lymphocytes and enters the cell.  (The virus has a special affinity for the CD4+Lymphocytes).  Once inside these cells the virus multiplies to produce many more of its kind.  Eventually these infected cells die or become too weak to work effectively.
  • This results in a weakened Immune System predisposing the infected person to many other diseases, which under normal health circumstances the body is able to fight.
  • Owing to overwhelming infections by these diseases which may multiply or too severe, the person becomes weaker and weaker and eventually dies.


(e)What is The First Stage of HIV Virus Infection?


Once a person is infected the HIV virus is transmitted all over the body attaching itself to CD4+Lympocytes.  This is called an acute HIV syndrome.


  • It prevents with skin rash, cough, swollen lymph nodes sore throat among others which then disappears.
  • The affected person tests negative to the standard HIV tests in this stage.




In this stage one can transmit the virus to another person.


(f)  Care and Support for those Infected and Affected


Persons living with HIV/AIDS require care and support as this can prolong their lives and ensure that the stigma is eroded and positive living is ensued.  Therefore, the following should be considered:


  1. Nutrition


  • They require a balanced diet to be in good health.
  • They should be encouraged to take meals regularly.
  • Meals of quality and quantity should be served to strengthen their bodies.


  1. Hygiene


  • They should be advised to keep themselves clean.
  • They should be observant of healthy aspects by avoiding infections and taking exercises regularly.
  • The affected i.e. wife of husband, children, relatives should support the sick in all ways possible.
  1. Emotional Support


  • The moods and feelings of the sick should be understood.
  • Sympathy sand empathy should be considered.
  • Other people should come in to support the affected so as to keep the former from fear and anxiety.
  1. First Aid and Home Nursing


  • The health workers e.g. community workers should equip the affected with First Aid and Home Nursing knowledge so as to render the appropriate service to those infected when need be.
  1. Developing Positive Attitudes


  • Other people should remove fear from the infected people.
  • The affected and other people should prepare the infected psychologically for the purpose of stable mind.
  • Religious support is vital and the affected should be encouraged to avoid fear and shame.
  1. Financial and Material Support


  • This is necessary as quite often the infected lose their sources of income.  This support will help to meet their basic needs e.g. food, bills, clothing and education fee.
  •  Also the affected may be orphans or parent/guardian may be weak to work for a living.




  1. Appropriate Information


  • The infected will require information on how to reveal their status to other people e.g. to a spouse.
  • They should be informed





It means giving the baby special injections or medicines to prevent him or her from catching serious diseases.




  • To protect children against dreadful diseases
  • Vaccinations provide immunity and when the disease emerges, it is easily managed.
  • To bring up healthy and upright human beings.

Immunization Schedule for Infants.


Disease                       Age                                                     Method of Immunization


Tuberculosis (TB)                  Birth & 5 years                                   Injection (BCG)


Diptheria, Polio                      3, 4 & 5 months                                  Injection

Whooping Cough &                                                                           Oral


Measles                                   9 months                                             Injection




In case of any need especially in the case of an outbreak of some disease, doctors will advise the mothers whether or not a new vaccine is required.

Safety when handling chemicals used at home


Chemicals are poisonous and care must be taken when using them to ensure proper protection. The following precautions should be observed:


  • Chemicals should be labeled appropriately and correctly to avoid confusion.
  • They should be kept away from children’s reach.
  • Chemicals should not be kept in the obvious places as this is tempting.
  • Keep chemicals separately according to their purposes.
  • Only knowledged persons should be allowed to handle chemicals to avoid
  • Personal protection should be observed e.g. when wearing hands after handling


3.9       Drugs



Drug is a medicine or substance which has marked effect when taken into the body.


  • This effect may be positive or negative to the user.




Drugs may be classified into two categories.


(i)  Legal Drugs:-


  • These are drugs or medicine that a doctor prescribes for depression.
  • The patient uses the dose for a certain period and according to the physician’s directives.


(ii)  Illegal Drugs:-


  • These are substances which when taken they alter the brain functions and create dependence.  The victim will be uneasy once they have skipped a fix.
  • Illegal drugs such as cannabis, ecstasy, LSD cause negative results to the user and should be avoided by all might.


Proper Use and Storage of Drugs:-


Drugs should be administered according to the doctor’s prescription.  Taking more or less than advised can be detrimental to one’s health.


  • When using drugs, time and duration are of paramount importance
  • Correct dosage enhances quick recovery and quite often the disease/ailments disappear for good.
  • Appropriate storage should be considered.  Drugs should be kept away from children’s reach.
  • Drugs will be affected by light and so it is advisable to keep drugs in enclosed  places where lighting is controlled.
  • Clear labeling is vital to curtail confusion.
  • The self-live of medicine should be considered.  This avoids use of expired drugs which could be poisonous to the users.


3.10     Drug and substance abuse




Drugs refer to all the substances which alter the organic functions and the behavior of thiose who take them.



Commonly abused drugs and substances


  1. Tobacco:-


  • Smokers inhale poisonous substances e.g. tar, nicotine and carbon-monoxide. This poisonous gas is also breathed in by non-smokers when they are close to smokers.
  • Tobacco produces its effect very slowly e.g. it can take decades to see the results of smoking.  Also some people may not seem to be affected by smoking.


Effects of Smoking


  • Tobacco causes diseases of the heart, cancer, stroke, bronchitis, bad circulation and


  • Pregnant women who smoke usually have smaller babies i.e. underweight babies.
  • Their babies have a great risk of death at birth.
  • Smoking habit is very strong smokers who wish to give up are unable to to do it on their


  • Smoking provokers withdrawal symptoms, thus they feel on intense desire to smoke

when they have not done it for a while.




According to WHO tobacco is the first preventable cause of death.


  1. Alcohol


The effects of alcohol are immediate.


  • Drinkers feel happy and talkative shortly after drinking. If they continue drinking they

become drunk.

  • Short term alcohol makes all the muscles including the heart numb.
  • Sharpness of the sight is lost particularly at night and with artificial light.
  • Personality changes e.g. the person becoming more impatient and aggressive.


Long Term


(i)    Drinkers have a risk of cirrhosis of the liver, a cancer of the mouth and esophagus.

(ii)   Drinkers run the risk of suffering from memory loss, hallucinations and degenerative




These are medications that doctors sometimes prescribe for depression.


  • Some are manufacturers in illegal laboratories
  • Some people use them to keep themselves awake.
  • They are usually in form of pills.  When illegally handled they are in powder form to be

snorted through the nose.

  • They may even be injected.




  • When taken feelings of euphoria and self-confidence follow.
  • When the effect passes, feelings of anxiety (fear0 and irritability appear.




  • It is very easy to get hooked on this drug.
  • The dose must be increased to achieve the high of previous times.
  • Those who use them can intoxicate themselves easily and suffer from hallucinations.
  • There is the tendency of becoming anti-social.




  • Cocaine can be taken in several forms
  • The most common form is by nosal absorption
  • It may also be injected or smoked in a cigarette or in a pipe.




(i)      Its effects are similar to those of amphetamines although the make-up is very different.

(ii)    Also the symptoms of intoxication are similar, but the hallucinations come quicker

(iii)   Repeated doses produce extreme agitation and anxiety.

(iv)   Excessive doses lead to death from respiratory depression, convulsions or heart rhythm

(v)    Intoxication by cocaine provokes the risk of accidents and sicides.




  • Cocaine is very expensive and this leads to frequent adulteration.
  • The adulterations cause very unpleasant effects and sometimes even death by poisoning.


5.MOMA – Ecstasy (Disco Biscuits. Adam, Arm Drug, e, XTC)


  • Ecstasy –  it is active ingredient is a stimulant known as MDMA
  • It is a designer drug (synthetic) similar to amphetamines
  • It is presented in pills, the size of a lentil.
  • It started out by being used as a drug in psychiatry, but it was made illegal in due to its risks.



  • An Ecstasy ‘high’ takes the form of a euphonic rush or a feeling of serenity
  • It produces nausea, dry mouth and a rise in blood pressure.
  • High doses over a long time can produce anxiety, panic confusion, insomnia and possibly psychosis, paranoia, etc.
  • Most of those who have died have exhibited symptoms connected with heart stroke.


It is tough that the accumulative effects of MDMA (which has a stimulant makes it possible for the addict to dance for long periods without feeling exhausted) and dehydration from dancing in hot night clubs.


  • Some evidence suggests that ecstasy triggers the body’s release of anti-diuretic hormones which limit the effectiveness of the kidneys at processing fluids.
  • Some people have responded to the stimulant aspect of drug with very high blood pressure, causing heart attack or brain hemorrhage.
  • Fundamental risk is its toxicity on the nervous system.
  • Difficulty in muscular co-ordination.
  • Cold feelings.
  1. Cannabis (Hashish, Marijuana)


It is a preparation from the dried flowering tops of the hemp plant and is smoked, chewed or  drunk to induce Euphoria.


  • Slang equivalents include ‘pot’, ‘grass’, ‘weed’, ‘dope’, and as a cigarette, ‘joint’ and ‘reefer’.
  • It may also be presented in the form of chocolate drops.



  • The effects are quick and smokers feel relaxed, talkative and unworried about their problems.
  • Regular smoking of cannabis affects certain mental functions e.g. it decreases memory, reasoning and capacity for resolving problems as it disturbs the connections between neurons.
  • It affects personal motivation.  Regular smokers are usually unmotivated, apathetic without goals or objectives and without goals or objectives and without the wish to succeed in anything.
  • Cannabis smoke is more carcinogenic than tobacco smoke.  A big % of the addicts of heroin and other hard drugs begin by smoking cannabis/marijuana.


  1. HEROIN (‘Horse’, ‘smack’)


  • Is a white odourless, bitter crystalline compound.
  • It is obtained from Opium, a substance from an oriental plant called the Opium Poppy.
  • It is injected into the veins or muscle and some people smoke or sniff it and others take it orally.




  • It is calming.  It takes away physical and psychological pain leaving a felling of pleasure.
  • It is a highly addictive narcotic (addiction sets in within months).  The beginners get hooked quickly, committing robberies and even homicide to get a ‘fix’.
  • Main lining – (injects into a vein).  This results in veins becoming swollen, blocked or collapsed.
  • Addicts feel euphoric.  This feeling lasts a few hours.  When this feeling leaves, they experience muscular pains, cold sweats, shaking, fever and diarrhea.  This shows another dose (fix) is needed.
  • For tolerance, addicts need a great dose.  As a result an over dose may be reached.  This leads to nausea, irregular breathing, convulsions, state of coma and death.
  • Premature ageing sets in
  • Chronic skin ulcers
  • Heart problems



Other Risks From Heroin


(a)  Decreased immunological systems.


  • The organisms lose defenses and tend to contact diseases.


(b)  Chemical Adulterations


  • Obtain more doses, the dealers use inexpensive substances some are very dangerous and can cause death.


(c)  Hepatitis and AIDS


  • The virus of these diseases is easily transmitted by the use of needles and syringes which have been used by other people.


(d)  Hematomas


  • The repeated injections produce internal injuries and deterioration in the tissues and prevent blood circulations.




Certain gases given off by dissolvent produce effects similar to those obtained by alcohol.


  • The presence of these dissolvent in glues, paints aerosols etc make many young people try these volatile substances.





  • The effects are immediate because they pass quickly into the blood stream and then reach the brain.
  • Similar to alcohol, sniffing drugs by these substances can be pleasant or terrifying.

Other Risks Are:-

The speed of their effects


  • People have died, asphyxiated when putting the spray in their mouths.
  • The sprays cause paralyzing of the respiratory tracts hence death.
  • It may lead to death after becoming unconscious when breathing in from a plastic bag with the substance in it.


  • Breaks-up of friendship and the near impossibility of establishing any kind of social relationship except with groups of fellow users with similar habits.
  • Diseases and the consequences of self neglect.
  • Poor health as a result of lack of appetite.
  • Mental functions are affected e.g. decrease in memory, reasoning and capacity for resolving problems because drug abuse disturb the connections between neurons.
  • Break-up of families.
  • When death occurs the affected people suffer a great deal.
  • The impossibility of acquiring or holding down a job because of thee effect of drugs on co-ordination balance and the ability to think and retain.


Safety When Handling Chemicals Used At Home


  • The physical properties of pure H
  • Which component part of the Scheme of Work would enable the teacher to prepare teaching Aids.



What is weather

This is a condition of the atmosphere at a certain place for short period of time  (a few minutes to a few years ) Compare this with climate ; Which is average weather condition of a particular place for a long period of time (30-35 years). The weather of a place changes from time to time

Why study weather?

The impact of weather in our lives cannot be ignored, our activities and behavior are directly or indirectly affected by weather

Some activities which are affected by weather include;

  1. Farming:  By studying  weather farmers would be able to decide the appropriate time for carrying out activities like; preparing the land for planting, spraying , harvesting and migration in normadic communities
  2. Animals can migrate from one place to another depending on weather changes e.g. wildbeasts migrate from Serengeti national park in Tanzania to Maasaimara in Kenya  in July/ August. Birds migrate from cold regions to wamer regions
  3. Some reporting activities can be planned depending on prevailing weather conditions. E.g. Mountain climbing, surfing and sailing, skiing and swimming
  4. Air travelers need to know the prevailing weather conditions of their destinations
  5. Knowlegde of weather conditions would help people decide on the type of clothing to put on

Elements of weather


This is air in motion. It is caused by unequal heating of the earths surface.

In hot regions air is heated up faster than in cold regions. The heated air becomes less dense and rises up. Cold air from the cold regions move to take the place of risen hot air


Point B is heated up than A. Air in B becomes less dense and movesup. Cold air from A moves to yake place of risen air in B due to pressure in B.

Globally there are wind systems caused by different positions of the sun as the earth resolves round it.

In march and September when the sun is at the equator, air is heated up and rises along the equator cold air moves from the tropics to the equator and causes inter-tropical convergence zone (ITCZ)

Winds control the temperature of a place. Cold or warm wind blowing into a place changes the temperature.


Heat from the sun causes water on the surface of the earth to evaporate into the atmosphere as water vapour. Plants give out water to the atmosphere through transpiration. Human beings give water to artmosphere through precipitation. As the water vapour rises up, it is cooled and condenses to form clouds. The clouds become heavy and fall as rain.


This is the hotness or coldness of a place or a thing. The earth is heated up by the sun. The earth radiates long wave energy which heats up air. Hot air moves up and cold air flows to replace it. This causes conventional currents.


This refers to the amount of water vapour in the atmosphere. Absolute humidity is the amount of water vapour in a given amount of air.

Relative humidity is the ratio of the amount of water vapour at a certain temperature to the maximum amount the air can hold at that temperature.

If the humidity is low air can be described as dry. If humidity is 100 % is dew point. Hot air is capable of holding more moisture than cold air.


Atmospheric pressure

This is the pressure exerted on the earth’s surface by air above it. The air pressure is as a result of the weight on the air objects below it. It is less at high altitudes and great at low altitudes. The atmospheric pressure at sea level is 760mm of mercury (760mmHg)


This refers to the sun rays reaching the surface of the earth. The sun produces huge amounts of radiant energy but only a fraction reaches the earth.

The rays from the sun can only reach us when there are no clouds. The type of clouds, determine the amount and duration of sunshine if there are no clouds, the intensity of sunshine is high.


Clouds are masses of tiny droplets of water or ice particles or both suspended in free atmosphere. Clouds are formed when water vapor condenses. Condensation is the process where water vapour changes into liquid state.

Formation of cloud depend on temperature, air pressure, humidity and wind.

There are three main groups of clouds i.e. high, medium and low

High clouds

They include cirrus, cirrocumulus and cirrostratus.

Medium clouds

They include altocumulus

The low clouds include:

  • Stratocumulus
  • Stratus
  • Cumulus
  • Cumulonimbus


Explain how the formation of clouds depends on:

  1. Temparature
  2. Air pressure
  3. Humidity
  4. Wind

Describe the appearance of the following clouds in the sky

  1. Cirrus
  2. Cirrocumulus
  3. Cirrostratus
  4. Altocumulus
  5. Stratocumulus
  6. Stratus
  7. Cumulus
  8. Cumulonibus


Various elements of weather can be observed and measured. Different weather instruments can be used for this purpose.


Various aspects of wind can be measured

Aspect Instrument for measuring the aspect
Direction Windvane
Strength and direction Wind sock
Speed Anememetre



This is a weather instrument for measuring direction of wind. It consists of a horizontal of wind. It consists of a horizontal arm in the shape of an arrow that rotates freely on a frame. There are other arms that show the four main types the four main compass directions.

The arrow of the windvane will always point to the direction from which the wind blows.


  1. Name materials that can be used to construct an improvised wind-vane
  2. Describe how the windvane can be constructed



This instrument shows both direction and strength of wind. It is a light cylindrical cloth bag or polythene bag attached to two rings, a big and smaller one.

It is tied to one end of a wooden post which is erected on the ground as shown above.



Describe how a windsock can be used to measure

  1. The direction of wind
  2. Strength of wind


This is an instrument which is used to measure the amount of rain falling in a place. Rain gauge consists of cylindrical container in which a glass can for colleting rain water is put. A funnel at the top directs water into a jar.

The diameter of the funnel is 13cm. The height of the funnel above is 30cm

This is to prevent water from splashing into the raingauge from outside. The cylindrical container is buried in the ground to avoid being dislodged by run off.

The rain gauge is placed in an open place. All the water collected is poured into a special measuring cylinder where the amount of rain can be read directly in mm.


  1. Name locally available materials that can be used to construct an improvised raingauge
  2. Describe how the rain gauge can be constructed using the materials named above.


This is an instrument used for measuring temperature. Commercial thermoter use either mercury or alcohol. These two liquids have the ability to expand when temperature rises and contract which temperature decreases.


They can show significant changes for small changes in temperature. The instrument consists of a glass bulb which is attached to a narrow glass tube. The narrow tube is enclosed in a larger glass tube. The bulb is filled with mercury and capillary tube is sealed at other end of the bulb


  1. Describe how the mercury or the alcohol thermometer works
  2. Give characteristics of mercury which makes it good as a thermometric liquid
  3. Compare the properties of alcohol and mercury as thermometric liquids.

Improvised air thermometer

How the glass bottle is warmed the air inside expands and pushes the liquid in the narrow tube which risen through capillary action downwards. This goes to record a higher temperature.

When the glass bottle is cooled the air inside contracts . A partial vaccum is formed and liquid is pushed upo by atomospheric pressure acting on it. In the basin. This leads to a lower leading


  1. Why is the liquid coloured?
  2. Why used tight titted cork?
  3. What is the underlying principle in the working of this instrument

Liquid thermometer

  • Colored water is put in a glass bottle.
  • An inner biropen tube is inserted into a cork which is lighting fitted to the mouth of the glass bottle.
  • A scale made from manila paper is fixed on the biropen tube using sellotape. The scale is graduated from bottom upwards such that high readings are at the top and lower readings at the bottom.

How does it work?

When temperature rises the coloured water expands and moves upwards through the tube to indicate high temperature. When temperature falls, the water contracts and the level in the tube drops to indicate low temperature.

Hair Hygrometer

  • This is an instrument used to measure humidity
  • Construct a wooden stand as shown in the diagram
  • Tie a hair strand to a nail fixed on the side of a stand. Tie it to a weight on the other end.
  • Pass the hair strand on a roller to which a pointer is fixed.


When the air is moist, the hair absorbs moisture and contacts linearly as it expands laterally. This results in shortening of the hair strand which pulls the roller upwards and the pointer indicates a higher reading.

When the air is dry, the hair relaxes and expands linearly. This pulls the roller downwards and the pointer indicates a low reading


This is a weather instrument for measuring atmospheric pressure

Mercury barometer

Mercury barometer is made up of glass tube which is open on one side. The tube is filled with mercury and the immersed vertically in a bowl of mercury with the open end facing downwards.

A column of mercury is supported by air pressure outside the tube upto 760mm above the mercury in the tube is vacuum.

Improvised Air Barometer

When the atmospheric pressure increases more than the pressure inside the bottle, the thin rubber sheet is pushed inwards and the pointer in turn moves upwards to record a high pressure

When the atmospheric pressure decreases the pressure inside the bottle, the thin rubber sheet is pushed inwards and the pointer moves upwards to record a high pressure.

When the atmospheric pressure decreases the pressure inside the bottle would be greater than the pressure outside. The thin rubber sheet is pushed upwards and in turn the pointer moves downwards to record a low pressure.


Weather station:

This is a place set aside for the purpose of observing , measuring and recording weather elements. These are mostly found in meterogiocal centers, agricultural institutions , schools and colleges.


For a weather station to serve its purpose effectively choice of a suitable site is important. The following factors need to be taken into account when setting up a weather station.

  1. It should be in an open place where there is free flow of air.
  2. The site should provide a wide view of the surrounding landscape and the sky.
  3. Site should be fairly level or gently sloping
  4. Site should be free from flooding


It is important to observe, measure and record weather on daily basis. The weather can be recorded on a chart symbols


The daily weather can be observed and recorded in the morning and afternoon on a chart as shown below



This is the predicting of the state of the atmosphere in a particular region over a period of 24 hours or 48 hours

Inorder to predict the expected weather condition, certain weather elements must be observed. These include wind direction, pressure , temperature, cloud cover.

The past weather conditions are also important in forecasting future weather phenomena.

Balloons carrying instruments are released into the atmosphere twice in a day.

The instrument transmit data back to receivers at the weather stations which is processed  to create weather forecast.

Today, satellites are used which transmit photographs on weather conditions daily.

The photographs show cloud systems give information on movement of cyclones


Traditional  beliefs about weather


Discuss the traditional beliefs about weather in your community

Discuss how the following factors affect weather

  1. Wind
  2. Distance from equator
  • Altitude
  1. Nearness to the ocean
  2. Humidity
  3. Cloud cover
  • Rain


This work should be done at home

Construct the following weather instruments

  1. Wind-vane
  2. Wind-sock
  • Rain gauge
  1. Air thermometer
  2. Liquid thermometer
  3. Air barometer
  • Hair hygrometer



Astronomy is the study of heavenly bodies that include sun, planets, moon, steroids, meteors

and comets.



A star is a huge ball of glowing gases.

  • There are countless stars in the sky
  • The sun is a star that is nearest to earth.
  • Some stars are bigger than the sun but appear smaller because they are further from

the earth.

  • Stars are of many different colours and size.
  • The colour of the star is an indicator of its temperature.
  • White stars are the hottest and red stars are the coolest.



  • These are groups of stars that form a recognizable pattern in the sky.
  • Some constellations include:-

(i)  Orion (Hunter)

– has more bright stars than other constellations.

– Can be seen during early months of the year





(ii)  Plough (Ursa major/great bear)

  • Has seven stars, with four forming a rectangle and three forming a tail
  • Observed when you face northwards.





(iii)  The Southern Cross

  • Group of four stars with a cross shape
  • Observed when facing south.



(iv) The scorpion

  • Brightest of all constellations
  • Shaped like a scorpion.





(v)  Canis major (great dog)

The brightest star in the sky is part of this constellation.


Large group of stars in outer space

  • Our solar system belongs to the galaxy called the Milky Way.
  • There are many other galaxies.

The Solar System

Consists of the sun and its family of planets together with other smaller bodies-: moons,

steroid belt, comets, meteors and dwarf planets.


The sun – centre of solar system

  • Revolves and within its gravitational pull are revolving planets.
  • Planets revolve round the sun in circular paths called orbits.



There are eight planets in solar system.

  • The planets are arranged in order



Small pieces of rock that circulate in space.

  • When a meteor enters the earth’s atmosphere, it burns up due to the

heat generated by friction with air.

  • This produces a streak of light in sky, called a shooting star.
  • Sometimes a meteor may reach the earth’s surface before it has burnt
  • out completely. It is then called a meteorite.

Activity: – Make a model of the solar system, showing the positions of planets, sun

and their paths.


Question: – What differentiates Saturn from the other planets.


Movement of the Earth

The earth has two types of movements:-

  • Rotation on its own axis
  • Revolution around the sun


Rotation of the Earth

  • Earth rotates on its axis once every 24 hours in an anti-clockwise manner

from west to east through 360 ̊ of increasing distance, away from the sun.

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.


  • The four outer planets are gland planets.


  • The two largest planets are Jupiter and Saturn.


  • The outer planets are gaseous in nature, but may have a solid core.


  • The four inner planets are smaller in size and are made of rock and metal.

Asteroid belt

  • Found between Mars and Jupiter.
  • An asteroid made of rock and metal.
  • Revolve round the sun like planets



  • Fairly large bodies which consist mainly of gases together with a few rocks.
  • When a comet passes near the sun it glows and forms a tail which point away from the sun.
  • This means that every one moment one side of the earth faces sun.
  • The side facing the sun experiences day time while the other time has night time.
  • The axis is an imaginary line through the centre of the earth from North pole to

South Pole.


Effects of rotation of Earth:-

(i)  It causes day and night

(ii) Causes high and low tides

(iii) Causes deflection of winds and ocean currents.

(iv) Causes time differences between longitudes


Revolution of the earth:-

  • It’s the movement of the earth around the sun.
  • Movement of the earth is in a path called orbit around the sun.
  • Revolution takes 365¼ days


Effects of revolution of Earth

(i)   It causes the four seasons in a year (summer, winter, autumn and spring) in

temperate areas.

(ii)  Longer days and shorter nights in northern hemisphere in June.

  • Shorter days and longer nights in northern hemisphere in December .i.e.

unequal days and nights.

(iii)  During summer each affected pole experiences 24 hours day light, while winter

each affected pole experiences 24 hour night.

(iv)  Changes in the position of the midday sun at different times of the year.


Phases of the moon

  • The moon is the earth’s natural satellite.
  • Rotates on its own axis
  • Revolves around the earth once every 29½ days.
  • The moon has no light of its own and reflects light from the sun.
  • Depending on how much of the lighted side of the sun we see the moon has several phases.


  • When moon is nearest the sun, the lighted side does not face earth and the

night is dark.

  • As it moves further from the sun it can be seen a little at a time.
  • The first appearance of the moon after a dark night is called new moon.
  • After 15 days it moves to the other side of the earth farthest from the sun.
  • At this time the earth is between the sun and the moon.
  • This stage is called the full moon and it can be fully seen from the earth.
  • Once again its size begins to decrease until it disappears from the sky and it is said to be waxing (getting bigger)
  • After a full moon, when the moon is getting smaller, it is said to be waning

(getting smaller)


  • A crescent is when less than half lighted side of the moon can be seen while when more than half the dark side can be seen it is said to be a crescent.


Assignment: – Draw an illustration showing the phases of the moon relative to the position of

sun, moon and earth.

















5.0 SOIL


Natural material on the earth crust which the roots of plants are anchored- (Top layer of the earth crust)

Types of soil.

Clay – which has few particles poorly drained   terms clocks when dry.

Loam – mix of sand and clay and has good amount of humus. Contain good amount of plant nutrients and best for agriculture most productive soils for crop production its characterized by most soils

Sand – / light soil

Characterized by large soil particles which are loosely packed.

– They are well aerated

– Heats up quickly

– Poor water holding capacity.

5.2.3 Composition of the soil.

(i) Mineral particles – are dissolved in water and absorbed by plant roots

(ii) Air found in the spaces between soil particles. Role – for respiration of plants of plants and other organisms.

(iii). Water – found as a thin film around the surface of the particles held by force of adhesion.

(iv) living organism

Include both large and micro organisms. They break down the plant residues. Nitrogen fixing bacteria add nitrates to the soils.

(v) Organic Matter- formed from the decomposition of dead plants and animal remains.


Improve soil aeration

Source of nutrients

Make ploughing easy.

Experiment to prove soil has the above

5.24 assignments

Soil profile

It’s the vertical arrangements of various soil layers horizon


-Horizon A – top layer dark in color because of humus

-Has a variety of decaying matter permeable to water

-Well aerated

Horizon B – less permeable to water and air than horizon A referred to as the layer of accumulation.

Horizon c- layer weathered parent lock. Contains gravel/coarse particles

Horizon D – parent rock / bed r where rock from where the soil is formed

Assignment – Model the soil profile

Soil texture

Refer to the relative proportions of the various sizes of mineral particles in a sample of soil.


Stone 72000mm gravel, 20mm -2000mm

Fine gravel 2omm – 0.2 mm

Coarse sand 0.2 – 0,002mm

Fine sand 0.2 – 0.02 mm

Silt           0.02 -0.002mm

Clay   – 0.002mm

The texture of the soil influences the growth of the crops.


Physical properties – assignment

5.2.7    Soil Erosion

It’s the removal and carrying way of the soil by agent of soil erosion agents.

– Water


– Animals

– mans activities.

Types of erosion

Splash erosion – removal of soil particles by the impact of the rain drops, the rain drops have energy, and this energy disposes the soil particles by detaching and transporting them in splashes.

Sheet erosion.Uniform removal of soil in thin layers caused by surface flow.

Rill erosion – removal of soil by water from small but well defined channels.(tills)

Gully erosion – it’s an advanced stage of till erosion. Its removal of soil from large channels (gullies).


Soil Fertility

Compound fertilizers – supply two or more nutrients at a time.

eg Nitrogen Phosphorus +potassium

N                P                      K

20                             20                    5

Manures organic manures Types

-Farm manure

-Green manure

-Compost manure

-Farm yard manure – consists of waste from the livestock dung, urine and beddings.

-Compost manure

-Gotten from decomposing of plant and animal materials.



Four heap system





Materials                                                                                                materials






Materials placed in heap labeled x after 5 weeks they are transferred to heap the labeled y.

After another 3wks they are transferred to heap labeled 7 then taken to the field for decomposition.

Green – made by ploughing or digging into the soil a growing crop.

Characteristics of a good soil for green manure:-

– Have high nitrogen content

– should have ability to decay rapidly

– should have the ability to produce lots of foliage

– should have the ability to grow fast

– should have the ability to grow in poor soils.

Assignment – advantage of fertilizer and manure.










At the end of the topic, the learner sho7ld be able to;

  1. State characteristics of plants.
  2. Classify plants.
  3. State the structure and functions of the main parts of flowering plants.
  4. Draw a flower and label the parts.
  5. Describe pollination and fertilization.
  6. Draw various seeds and label the parts.
  7. Explain agents and significance of seed and fruit dispersal.
  8. Describe the process of germination
  9. Design experiments ton show conditions, types and stages of seed germination.
  10. Explain the meaning of vegetation reproduction.
  11. Identify types of vegetation reproduction.
  12. State the advantages and disadvantages of vegetative reproduction.
  13. Identify different types of crops .crop pests and diseases.
  14. State the effect of crop pests.
  15. State the effects of crop diseases.
  16. State methods of controlling the pests.
  17. Identify common weeds and state methods of controlling the weeds.
  18. State signs of wealthy crops.



Plants show the following characteristics:-

  1. They respire.
  2. They reproduce.
  • They grow.
  1. They excrete.
  2. They reproduce.
  3. They respond to stimuli (irritability).
  • They feed. Green plants their own food trough photosynthesis. fungi or non-green plants obtain food from decayed organic matter.



Plants can be classified into

  1. Green plants and non-green plants.
  2. Flowering and non-flowering plants.



The plants have a green pigment called chlorophyll in their leaves that gives them the green color.

Green plants make their own food through a process known as photosynthesis.


  • Maize
  • Beans
  • Tea
  • Kales
  • Trees



They lack chlorophyll and and therefore don’t make their own food.  They obtain their food from decaying organic matter.


  • Mucor (mould)
  • Ring worms
  • Penicillin
  • Yeast



  • The plants do not produce flowers
  • They reproduce by spores or budding.


.  Mosses

.  Liverworts

.  Fungi

.  Ferns


  • They produce flowers.
  • They are classified into

.  Dicotyledonous

.  Monocotyledonous

  • They have two cotyledons or seed leaves.
  • Their leaves are net veined and broad in shape.
  • They mainly have a tap root system.

E.g. Herbs such as beans, cabbage, tomatoes, pigweed, tomatoes and black jack.

  • Shrubs

Eg Coffee, tea, hibiscus

  • Trees

E.g. mango, lemon, avocado, eucalyptus and oak tree.


  • They contain one seed leaf or cotyledon.
  • They have narrow leaves with veins running parallel to each other.
  • They have a fibrous root maize, barley, wheat , millet , sorghum , Napier grass.

A plant is made up of three main parts. They include.

  1. Leaves
  2. stem
  • roots


A leaf is made up of a stalk (petiole) , lamina , veins , mid-rib , margin and apex.

Internal structure of a leaf

Scan the internal structure of a leaf

Ref. distinction science for P.T.E page 101 figure 6.11(a)


Functions of the leaf

  1. photosynthesis
  2. respiration
  3. transportation
  4. gaseous exchange
  5. excretion of excess water


Stem forms the lower parts of the shoot that supports brunches, leaves, and flowers

  1. Functions of a stem
  1. Supports the branches, leaves and flowers.
  2. Transports food from leaves to other parts and water and mineral salts from roots to leaves.
  3. Some stems store water e.g. cactus
  4. Some plants store food e.g. sugarcane
  5. Green stems also carry out photosynthesis
  • A stem is composed of the following parts.

.  Epidermis

.   Pericycle

.  Cortex

.  Cambium

.  Phloem

.  Xylem

NB   Scan the transverse section of a stem on page 120 primary teacher education science.


ROOTS- Part of the plant that normally grows underground

Functions of roots

  • Anchorage of the plant firmly in the ground.
  • Absorption of water and mineral salts from the soil.
  • Storage of food eg in carrots and cassava.

There are two main root system

  • Tap root
  • Adventitious (fibrous) roots

Structure of roots

Internal structure of a root consists of

.  Epidermis

.  Cortex

.  Vascular tissues

.  Root hair

.  Pericycle

.  Endodermis


NB Scan figure 6.7 young monocotyledonous root

REF Distinction science pp 98 P.T.E



A flower is the reproductive system of a plant.  It is the reproductive structure in flowering plants.

  1. Structure of a flower.

A flower is made up of the following main parts.

  • Receptacle / stalk
  • Sepals (calyx)
  • Corolla
  • Stamen .{ anther , filament} male parts of a flower
  • Pistil {stigma, style, ovary} female parts of a flower.

NB   scan structure of a flower on pg 124 P.T.E science year 1 and 2



The main function of flowers is to facilitate sexual reproduction in flowering plants.


This is the transfer of pollen grains from the anther to the stigma.

There are two types of pollination

  1. Self pollination- This is the transfer of pollen grains from the anthers to the stigma of the same flower and another flower of the same plant.
  2. Cross pollination- This is the transfer of pollen grains from the anther to the stigma of another flower on a different plant of the same species.


1a)  State the agents of pollination.

  1. Describe characteristics of insect and wind pollinated flowers.



This is the fusion (joining together) of the nuclei of the male and female garmets to form a zygote.

After pollination the pollen grains germinates and forms a pollen tube which grows downwards through the style and gets into the ovary.

  • At the tip of the pollen tube is a tube nucleus and behind it are two male gamete nuclei.
  • The pollen tube enters the ovule through the microphyle and penetrates the embryo sac releasing the two male gametes nuclei.
  • One nucleus fuses with the female egg cell (gamete) to form zygote. Zygote later forms the embryo.
  • The other nucleus fuses with diploid nucleus to form triploid primary endosperm which forms the endosperm. The fusion of the two male gamete nucleus at the same time is called double fertilization.


NB Scan the diagram on page 128 P.T.E science.


A seed is a small embryonic plant that is enclosed in a seed coat.

It consists of

  • Testa- outer covering that protects the seed.
  • Hilum- A scar on the seed coat where the seed was atched to the ovary wall
  • Microphyle- A tiny hole in the testa.
  • Radical- p[art of the seed that grows into the root.
  • Plumule- part of seed that grows into a shoot.
  • Cotyledon- seed leaves which contain food reserved used during early stages of germination.


Seeds dispersal is the spread of the seeds from the parent plant to new areas.

  1. Significance of seed and fruit dispersal
  • It enables seeds reach to the ground where there are suitable conditions conditions for germination and growth.
  • Dispersal gives the seedlings higher chances of survival by growing far apart from each other.
  • Seed dispersal ensures colonisation of new areas by plants, this improves bio diversity.


  1. Agents of seed and fruit dispersal.

Agents of dispersal includes includes.

  1. Wind
  2. Water
  • Animals
  1. Self dispersal mechanism

Seeds and fruits have adaptations that favor dispersal by a particular agent



Explain how the following agents help in seed and fruit dispersal

  1. Wind
  2. Water
  • Animals
  1. Self dispersal



Germination is the process by which a seed develops into a seedling.

During germination

  • Water enters the seed through the microphyle and diffuses into the cell of the endosperm this softens the testa and makes it to swell up.
  • The starch and protein in the seed are digested to soluble forms by enzymes in the seed.
  • This passes to the growing radical and plumule.
  • The radical then grows out through the microphyle and downwards into the soil.


Conditions necessary for germination.

To germinate a seed requires water, oxygen and warmth


.  It promotes the medium for enzymes to act

.  It dissolves the broken down food.

.  It transports the dissolved food substances to growing parts.

.  It softens the seed coat to facilitate the emergence of the radical.



It is required for oxidation of food substances stored in the seed.



Temperature influences the activity of enzymes involved in germination.  High temperatures denature enzymes.  Optimum temperature for seeds to germinates 30o c


The following materials were provided to investigate the conditions necessary fo germination.

  • Four test tubes
  • Bean seeds
  • Cotton wool
  • Oil
  • Hot water

Using the above materials design experiments to show conditions of seed germination.



There are two types of germination

Hypogeal germination

This occurs in monocotyledonous like maize in this type the seedlings or cotyledons remain below the surface of the soil.

Epigeal germination

This occurs in dicotyledonous like beans in this type the seed leaves remain on the new shoot and are brought above the ground.


It is a form of a sexual reproduction where by a new plant grows from a part of the plant e.g. stem.

Types of vegetation reproduction

They include

  1. Corms
  2. Bulbs
  • Rhizomes
  1. Stem tubers
  2. Creeping stems e.g.- runners


– Suckers

  1. vi) Root tubers e.g. sweet potatoes.



Draw and write a brief description of

  • Corns
  • Bulbs
  • Rhizoids
  • Stem tubers
  • Runners
  • Stolons
  • Suclcers


  • Crops mature faster compared to use of seeds.
  • It is easier and faster to propagate especially where seeds have prolonged dormancy.
  • Plants that cannot produce seeds can also grow successfully.
  • Resulting plants have desirable characteristic such as disease and pest resistance.
  • The offspring is similar to the parent.



  • Difficult for new crop varieties.
  • Planting material cannot be stored for a long time.
  • Materials are bulky and difficult to handle, store and transport.
  • Diseases or pests are easily transmitted to the new plant.
  • Sometimes it requires skill to carry out desired propagation method.


6.2.8                                                                CROPS


Plants grown for economic purpose or consumption.

Types Food Crops

  • Cereals –maize, wheat , barley. They give use to grains eaten when cooked.
  • Legumes – beans, soya beans, ground nuts. Roots of legumes have nodules.
  • Vegetables – have fibre and nutrients protect the body against diseases. They can be root or leaves.  Root vegetable carrots, beetroot turnip.  Leave vegetable – spinach .lettuce, kales.
  • Fruit – have fibre and vitamins. Important for protection e.g. mango. Oranges Avocado.


Grown for economic purpose (income) they are:-




Beverage make drinks – tea, coffee or cocoa.

They vary on the parts of plants harvested to make them e.g. tea leaves, coffee seeds


Priovide fibre e.g.




The fibre can make baskets, bags, mats, ropes.


Oil Crops


The plants provide oil e.g.







Divided in two categories


  • Field pests
  • Storage pests

Pests any animal/insects which is destructive to the crop.


Field Pests


Aphids – attack cabbage, beans, citrus and suck juice.

Cut worms – attack seedlings cutting them at the base.

Termites attack sugarcane, cassava, maize eat planted materials.

Insects – damage leaves, flowers, fruits by chewing.


Storage pests – they attack the produce in the stores e.g. rodents, weevils, white ants.



  • Damage the produce
  • Reduce value of the produce
  • Poison and contaminate produce




  • Complete drying of produce
  • Dusting the produce
  • Good sanitation in stores
  • Distance of the store should be far from the field
  • Rat proof metals


6.2.10                                                         CROP DISEASE


Deviation from good health.Signs of unhealthy crops.


  • Wilting of crops
  • Discoloration of leaves
  • Lodging of crops
  • Necrosis – patches on either leaves or fruits
  • Rotting of fruits
  • Curling of leaves
  • Malformation


Harmful effects


  • Lower crop yields
  • Lower quality of produce
  • Cause food poisoning (aflatoxin)
  • Increase cost of production
  • Lowers farmer’s income.


6.2.11                                                              WEEDS


Definition – a plant growing where it is not needed.

Types of Weeds

  • Annual
  • Biannuals
  • Perennials


Assignment identification of various types of weeds


Advantage of weeds


  • Used as vegetables
  • Used as animal feeds
  • Cover soil against erosion
  • Provide herbal medicine
  • Produce toxic substance that can kill pests.




  • Weeds compete with plants for nutrients.
  • Weeds increase cost of production
  • May be poisonous
  • Reduce land value
  • Lower quality of pastures


Control of Weeds

  • Cultural
  • Mechanical
  • Chemical
  • Biological
  • Legislation


Cultural Method


  • Mulching
  • Use of certified seeds
  • Early planting
  • Use of crop rotation
  • Use of fertilizers and manures
  • Proper spacing
  • Flooding


Assignment on chemical use.













7.1.      Specific Objectives

At the end of this topic, the learner should be able to:

  1. State the characteristics of animals
  2. Compare the characteristics of animals and plants
  3. State general characteristic of the main group of animals
  4. Classify animals according to their characteristics
  5. Describe structure and life cycle of insects
  6. State the difference between complete and incomplete metamorphosis
  7. Identify products of farm animals
  8. Classify farm animals according to their products
  9. Define livestock parasites
  10. Identify livestock parasites
  11. Compare livestock parasites
  12. Classify livestock parasites
  13. State effects and control measures of livestock parasites.
  14. Identify signs of ill-health in livestock
  15. State effects of livestock diseases
  16. Identify different types of animal feeds
  17. Describe balanced diet for a farm animal
  18. Compare animal feeds
  19. Describe methods of grazing
  20. Compare methods of grazing.

7.2.0 Content

7.2.1. General characteristics of animals

  • They feed
  • They breakdown food to release energy (respiratory)
  • They excrete
  • They undergo growth and development
  • They reproduce
  • They move
  • They respond to stimuli (irritability)

Comparison of characteristics of animals and plants



1 Growth occurs in all parts of the body at the same time and stops on reaching a certain age. 1 Growth occurs in localized areas like root apex and meristems and continue until death
2 They feed on readymade food 2 They make their own food during photosynthesis
3 Animals move their whole body from one place to another 3 Movement is by growth.  Some lower plants move from one place to another
4 Animals respond to stimulus immediately 4 Plants take long to respond


These are animals which do not have backbone (notochords)

Invertebrates can further be subdivided into the following phyla

  • Protozoa
  • Porifera
  • Coelenteratea
  • Playtyhelminthes (flatworm)
  • Nematoda
  • Anielida
  • Mullusca
  • Echinodermata
  • Arthoropoda

i).       Protozoa


  • They are single celled
  • They can be found in fresh water, the sea, damp soil, and in the blood of animals and humans
  • They reproduce through cell division
  • They move from one place to place
  • Example –amoeba, paramecium, plasmodium and euglenas.



  1. ii) Porifera


  • They are made of many cells
  • Females produce fertilized eggs
  • They do not move. They are endorsed to rocks or ocean buttons
  • They are found.


iii)        Coelenterates


  • They are cylindrical in  shape
  • They are made of two layers
  • Most of them have stinging cells
  • They have one opening in their bodies
  • They are aquatic
  • The mouth is surrounded by tentacles e.g. hydra, jerry fish, sea anemone and coral


  1. iv) Echinoderms


  • Some have spines which may be used to give poisonous stings
  • Their bodies have radical symmetry
  • Others have  hard skins instead of spines
  • Star fish, sea urchins and see cucumber
  1. v) Molluses


  • They are soft bodied and unsegmented
  • They can live in sea, fresh water or on land.
  • Some have shells-some may have one or two shells
  • Examples: snails, oyster, catfish, squid, slugs, octopus
  1. vi) Annelids


  • Their bodies are made up of a number of rings or segments.
  • They are soft bodies and shining
  • They breathe through their skin
  • They have a mouth, anus, male and female reproductive organs

Examples e.g. earthworm, leeches, sandworm, lungworms.

vii)    Nematodes



  • They have long thin unsegmented bodies
  • They have round body with pointed ends.
  • They have a complete digestive tract i.e. gut, with mouth and anus
  • Some are microscopic while others are 10cm long
  • Most are parasites and live in other living animals or plants










Platy helminthes (flatworms)



  • They have no circulatory system
  • Use cilia rather than muscle for locomotion
  • They are flattened and segmented
  • Digestive system is either absent or much reduced
  • Most of them are parasites
  • The reproductive system is hermaphroditic




Liver fluke

Tape worm


They can further be subdivided into the following classes









  • They have segmented bodies.
  • They have chitinous exoskeleton or cuticle that covers the entire body
  • They move by jointed appendages (limbs)
  • There is periodic shedding of exoskeleton (moulting or ecdysiast)
  • Their vascular system is composed or hear, vessels and haemocoel
  • They posses two types of excretory organs

Malphigian and tubules and saccyules


They have well developed sensory organs

Examples : ticks, locusts, scorpion

Arthropods can further be subdivided into for main groups.

  1. Constraceans e.g. crabs, wood louse, pawns and lobsters


  1. Insecta (insects belong here e.g. butter flies, lallybords, bees, dragon flies


  1. Aradinids e.g.   mites, spider and ticks


  1. Myriapods e.g. Millipedes and centipedes



These are animals with a backbone.  They can be grouped into five phyla.


  1. Pieces              –           e.g. fish
  2. Amphibian                  e.g.      newts, toads, frogs and salamanders
  3. Reptiles                       e.g.      snakes, turtles, tortoise, lizards and crocodiles
  4. Ave                 e.g.      all the birds
  5. Mammalia                  e.g.      humans
  1. Ave



  • They have two pairs of limbs. Fore limbs are adopted for flying while the hind limbs are adopted for walking.
  • Most can fly but a few cannot
  • They are warm-blooded
  • Their bodies are covered with feathers
  • They have beaks with no teeth
  • They lay eggs which are covered in hard shell

Examples:   chicken, penguin, ostriches, ducks and cranes.



-They have a moist skin

-They live in both water and land

-They lay eggs in water which are fertilized externally

– They have gills for breathing when young and lungs when adults

– They do not have scales on their bodies

-Their body temperature changes according to that of the surrounding



-Their bodies are covered with dry scales; some like tortoise have shells

-They use lungs for breathing

-They are cold blooded

-Most except snake have four short limbs

_They reproduce by laying eggs which are internally fertilized. A few give birth to the young        ones

-They mainly live on land with a few living in water




-They are all aquatic animals

-They breathe by means of gills

-The body is covered with scales

-They lay eggs which are fertilized outside the body

-They have fins for movement

-Their body temperatures changes with the surrounding environment



–           They have fur or hair in their bodies

–           They have mammary glands and feed their young ones on milk

–           They are warm blooded

–           They have two pairs of limbs

–           They use lungs for breathing

–          They have large complex brains

–           They have teeth of different types

Their heart and lungs are separated from the abdomen by the diaphragm

They give birth to live young ones except duck-billed platypus which lay eggs

Mammals have internal fertilization; examples of mammals are whale, human gorillas,           and elephants


7.2.2.   Insects

They belong to the phylum arthropod and the class insect. They belong to the largest             single class of animals.

            Structure of insects

The insect body is divided into:-

  1. Head
  2. Thorax
  3. Abdomen
  4. Head

–  It has a pair of antennae or feelers and a pair of compound eyes. The mouth is                                       also found on the head.


  1. Thorax

-It has three segments.

– Most insects have two pairs of wings.

-The first pair is attached to the second middle segment.

-The second pair is attached to the last segment

-Some insects have only one pair of wings e.g. mosquitoes and house flies

-Other insects have no wings e.g. ants

  1. Abdomen

The abdomen is segmented .These segments contain spiracles through which the insects             breathe

The life cycle of insects

Life cycle of insects involves changing in form from one stage to the other.. Insects lay             eggs which hatch into young ones. Most young ones differ from adult insects. The series   of         molts and changes that transform the immature form into adult is called metamorphosis.

            Types of Metamorphosis

There are two types of metamorphosis;

  1. Complete metamorphosis
  2. Incomplete metamorphosis
  3. Complete Metamorphosis

There are four stages involved in complete metamorphosis.

Egg- Larva- Pupa-Adult

The insect lay eggs which hatch into larvae .The larvae is quite different from in form behavior from adults. They are called grabs, maggots or caterpillars depending on the             species of the insect. The larva is a vicious feeder and the most destructive stage of the       insect pests. It sheds its cuticle several times and grows rapidly.On reaching full size the            larva becomes inactive, neither feeding nor moving. Extensive breakdown and      reorganization takes place within its body, eventually giving rise to pupa. Pupa is a             prolonged resting stage. Further changes take place giving rise to adult.

Examples of insects that undergo complete metamorphosis are butterflies, house flies, mosquitoes and bees.

  1. Incomplete metamorphosis

This is where some insects undergo three development stages e.g cockroaches,             grasshoppers and locusts.

The three stages are;

Eggs- Nymphs-Adult

Eggs hatch directly into smaller insects called nymphs which look like the adult except             that they are smaller. Nymphs molt five times and the stage between each molt is called instars’.

Each instar last for 4-5 days. The fifth instars takes 8 days after which it changes             into      adult.

Nymphs move by crawling or leaping with hind eggs.

7.2.3 Farm animals

Classification of farm animals according to their products


  • Dairy animals-for milk production e.g. Guernsey, Jersey.
  • Beef animals for meat production e.g. Aberdeen angus, boran.
  • Dual purpose for both milk and meat e.g. Red poil.
  • Sheep kept for-:

Wool e.g. merino, muttondorper, dual purpose – corriedale

  • Goats kept for hair – Angora goat, meat – black head Persia, milk – Toggenburgh
  • Pigs kept for pork- for pork- middle white, bacon-large white,

Dual purpose – saddle back.


Poultry kept:

Eggs – e.g. Light Sussex

Meat – e.g. hairy Sussex

8)  Rabbits-kept for-:

Meat –  e.g. Newzealand white

Fur – Angora rabbit

9) Ash kept for  -Meat e.gTillapia

10) Bees kept for:-

  • Honey
  • Wax
  • Pollination


7.2.4 Livestock parasite


Definition of a parasite

Parasite -organism that depend on another organism for survival.


Types of parasites

  1. a) Internal parasites
  2. b) External parasites
  3. a) Internal – The living within the body of the animal e.g.

– Round worm

– Tape worm

– Liver flukes

– wire worms/ thread worms


  1. b) External parasites

They live on the body of the  animal e.g.

  • TseTse fly
  • Keds
  • Ticks
  • Fleas
  • Lice



  • Cause aneamia
  • Reprieve the host animal food
  • Injury and damage the tissue of animal
  • Biting parasites – break the skin of animal exposing it to secondary infection.
  • Transmit disease transmission
  • Cause infection
  • Obstruction of internal organs


  • Use of de-wormers
  • Keep animal house clean and disfested
  • Keep feeders and wterers clean
  • Use of latrines by farm workers
  • Proper inspection
  • Control of fresh


7.2. 5 Livestock diseases

Definition of a disease

A disease is any deviation or alternation in the state of an animal or its organs which interrupts the proper performance of its functions.


Signs of ill health

  • Stunted growth
  • Loss of weight
  • Reduction in production
  • Rough coat
  • Coughing
  • Blood in stool
  • Poor appetite
  • Diarrhea
  • Change in temperature
  • Swelling on the body parts
  • Limping



  • Low yields
  • Reduction in quality of products
  • Transimission of diseases to human beings.


Shorteus  the productive live of the animal (through death)

Increase cost of livestock production.


7.2.6 Animal feeding

Types of animal feeds

(a) Roughage – These are feeds with high fibre contents in them

Eg .

-nappier grass





  • Have high fibre
  • Usually low in energy and protein
  • Constitutes main diet for luminants.

(b) concepts feeds with high level of nutrient/nutrients in them


  • ground cakes
  • Fish meeal
  • Bone meal.




  • Have high nutrient content
  • Have low fibre content
  • Constitute main diet for non – luminants.
  • Readily digestive and soluble.


Methods of grazing                   


There are various methods of grazing cattle.


  • Rotational grazing \zero grazing
  • Herding


Rotational grazing

Under rotational grazing animals move from one place to another when the farmer realizes the pastures/grass is finished.

Example of rotational grazing :-

  • Padlocking\strip grazing
  • Ferthering


Advantages of rotational grazing

  • Good varieties of grass continue
  • High milk yield
  • Isolation is possible
  • Control of diseases
  • Disadvantages
  • Require big pieace of land
  • Expensive



Zero grazing / stall feeding

Zero grazing is when dairy cattle mostly high yielders are realed in a confined area/ a stall.

It’s a remote mto



  • High yield is experienced
  • Control of breeding
  • Small area utilized
  • Control of parasites
  • Control of diseases



  • Labour intensive
  • Expensive



  • This is the grazing of animals in open places.

It’s a remote method of heardinganimals,but highly applicable in pastrol community.



8.1 Specific objectives

8.2.0 Content

8.2.1 States of Matter and change of state

8.2.2 Properties of solid and their applications

  • Hardness
  • Density (of regular and irregular solids)
  • Pressure
  • Expansion and contraction
  • Brittleness
  • Solubility

8.2.3 Properties of liquids and their applications

  • Boiling point
  • Pressure
  • Density
  • Shape
  • Miscibility
  • Expansion and contraction
  • Viscosity
  • Capillarity
  • Surface tension
  • Adhesion and cohesion

8.2.4 Properties of gases and their applications

  • Pressure
  • Weight
  • Expansion and contraction
  • Volume
  • Air
  • Composition
  • Uses
  • Mixture
  • Types of mixtures
  • Separation of mixtures

8.2.1 States of matter and change o f state

What is matter?

In order to understand what matter is carry out the following activities

Activity 1

Observe inside your class and list everything you can see, feel or touch.

From your list

  1. Which things occupy space?
  2. Do they have mass?

Matter is anything that occupies space and has mass.

States of matter

Matter can be classified into three states.  Thus solid, liquid and gas



Matter is made up of particles.

Activity 2

Take a sheet of paper and cut it into two.  Take one of the pieces and also cut it into two.  Repeat the activity for six times.

What do you observe?



The paper can be cut into very many minute pieces and this can go on and on.


Activity 3

Take a piece of chalk and crash it using a piece of stone and observe.

In activity 1 and 2, it can be deduced that matter is made up of small particles which can closely held together.

Kinetic theory states that matter is made up of particles which are always in a state of continuous random motion.

In solids the particles are very close together and forces of attraction between them hold them in rigid positions.  The particles can only vibrate about their fixed positions.  Solids have definite volume and shape.  When solids are heated they absorb energy and the particles vibrate faster.  This continues until the forces between them are weakened and the solid to liquid is change of state from solid melts.  This is change of state from solid to liquid.

In liquid state, the forces of attraction between the particles in high but not as in solids, the vibrations, the liquid particles can slide over each.  This explains why liquids have definite volume but no definite shape.  Liquids will occupy the shape of containers they are put in.

When liquids are heated, they absorb energy and the temperature rises until a paint is reached where forces of attraction between the particles is completely broken.  This occurs at boiling point.  The liquid changes to gas where particles can move independent of each other.

In gaseous state only weak forces of attraction exist between the particles.  This is vanderwaals forces.

The gas particles can move independent of each other.  This explains why gases have no definite volume and no definite shape.  Gases assume the volume and shape of containers where they are put.



Melting                                 Vaporization

Freezing                               Condensation


On cooling, gases condense to form liquids, liquids freeze to form solids.




This is the ability of a solid to resist scratching, bending and breaking.  Solids that are hard do not break easily.

Examples of hard substances are metals, diamond and glass.

Those that are easily, scratched, bend or broken are soft.  Examples are soaps, some plastics or sponge.

Some solids change shapes on hammering without breaking.  Then form sheets.  Such solids are said to be malleable e.g. Iron.

Other can be pulled to form strings or wires.  Such solids are ductile.  Ductility in the ability to be pulled into wires without breaking.

Hard solids are used in bending constructions; construction of bridges and other structures which are durable.


This is inability of a solid to bend due to lack of elasticity.

Elasticity is the ability of a substance to regain its original shape and size after distortion or when pressure is applied.

Brittle solids crack and break when force is applied on them.

Examples of brittle substances: glass, chalk, porcelain and dry clay.


Density of solid is defined as mass of the solid per unit volume.  The units of density are g/cm3 or kg/m3.

Exp.To determine the destiny of a solid with regular shapes.

Materials:  wooden cuboids, rulers, spring balance.


Measure the dimensions of the regular solid.  Weigh out the solid to determine its mass.


V = axb x c cubic units

=  abc cubic units

Mass, M =  mg


Density  = Mass


=  m   g/cubic units

g            m       g/cm3








For cuboids, volume given by length x height


In cylindrical objects

V  =  IIr2h


Density of irregular solids

Method 1

Fill a measuring cylinder halfway with water.  Read out the volume of water.  Tie the irregular solid and lower it into the water.  The solid displaces the water upwards.  Read off this final reading.

The volume of the solid would be;


Final reading – Initial reading


Weight out the solid to determine its mass

Method 2

Use of overflow can

Fill an overflow can with water until it flows through the spout.

Tie the solid with a thread and immerse it in the water.

The solid displaces its own volume of water which is (detected in a measuring cylinder and the volume read off.



The solid is weighed out to determine the mass.


Density   =      Mass



  1. Vehicle bodies are made of materials which are hard but of low density e.gAluminium whose density is 2.7 g/cm3.
  2. To put up structures engineers need to know the weight of the building materials to see if the foundations can sustain the weight.  This can be calculated if the densities of the building materials are known.
  3. Substances can be distinguished if their densities are known.  Pure gold has density of 19.2 g/cm3.  Therefore by determining the density it can be established if a given sample of gold is pure or impure.
  4. Density of nitrogen earlier known by scientists was found to be different from that of nitrogen prepared from chemicals.  This led to investigations to discover Argon, one of the inert gases.



Pressure is defined as force acting per unit area. Units of pressure are, Newtons/Square meter (N/M2).  This unit is also called Pascal (Pa).


1 Pa = 1N/M2.

Exp.  To determine pressure exerted by a glass slab when resting on a table with different faces.

Take a glass slab


Weigh out the glass slab to determine its weight.

Measure out the edges using a ruler or a tape measure.

Calculate the area of faces A, B, and C using the formula.

A  =  L x breadth


Pressure when slab is resting on the table with face A.

=    Weight of the slab

Area of face A


Pressure when slab rests with face B.

Record the data in the table below.



Face Force (N) Area (cm2) Pressure (N/M2)



The pressure varies depending on the area of the face.  The smaller the area the larger the pressure.



  1. Sharp objects exert more pressure than blunt ones.
  2. Carrying a bag with wide belt reduces the pressure exerted on the shoulder.



Write down among other applications of pressure in solids.


Expansion and contraction

Activity 4

Ball and ring apparatus

  1. Take a ball and apparatus, pass the ball through the ring.
  2. Heat the ball and hold it to pass through the ring as before.
  3. Allow the ball o cool and try to pass it through the ring.
  4. What do you observe in all the cases?





Initially the ball passes through the ring.  On heating the ball does not pass through the ring.  This is because it expands.  On cooling it passes through the ring since it contracts.  Hence solid expands on heating and contract on cooling .


Activity 5 (In groups)

Design two other experiments to show that solids expand on heating and contracts on cooling.

(Nail and tin can and wire expansion apparatus)

Different solids expend on different rates.


Bimetallic strip

This consists of two metal strips of same size but different expansion rates e.g. iron and brass.


Activity 6

Heat the bimetallic strip made of iron and brass.  Observe.




Before heating, that strip is straight.  On heating it bender in such a way that brass is on the outside of the curve. This is because brass expands faster than loan and therefore because longer.  Since the two metals are rewetted together brass would be on the outside of the curve since longer than iron.


Disadvantages of expansion in solids


  • Cracking of the chimney of an hurricane lamp. If some water falls on the grass of  a hot lamp, it suddenly contracts from outside when it is expanding from inside and this loads to cracking.
  • If hot water is poured into a thick glass, if cracks since it expands from inside more than outside. Pyrex glass with low expansion rate can be used to minimize this problem.
  • Fences and power lines appear longer in hot weather. So when erecting them an allowance should be given for expansion and contraction.
  • Railway lines have gaps left between them to allow for expansion in hot weather.
  • Steel bridges are not fixed at ends and made to rest on rollers at one of the ends. This allows them to slide easily when they expand in hot weather.
  • Hot water powered on utensils can distort their shape due to sadden expansion.


Uses of expansion


  1. When glass stoppers stick in the necks of glass bottles, the mouths of the bottles can be warmed to expand and allow the stoppers to be removed.
  2. Rivets to join metal plates are first heated to be red hot before they are hammed until the ends are rounded.  When the rivets cool they contract and hold the plates tightly together.
  3. Weathering of rocks take place due expansion in hot and contraction in cold weather.  The alternate expansion and contraction lead to breaking of the rocks.
  4. Thermostats are used to automatically switch on and off electrical appliances like pressing box, water heaters and refrigerators.   They have a bimetallic strip which bends on heating to break circuit and strengthens on cooling to make the circuit at different temperatures.  Hence can be used to maintain a certain temperature range.


Activity 7

To investigate substances that are soluble and those that are insoluble in different liquids.


Materials:  sugar, salt, chalk powder, soil, water, kerosene, cooking oil, containers, stirrer.



  1. Put some water into a transparent container until it is quarter full. Add a half spoonful of sugar into the water, stir and observe.  Repeat the experiment using salt, chalk powder and soil.
  2. Repeat the process using kerosene instead of water.
  3. Repeat using cooking oil instead of water.


Record your observations in the table below.  Where soluble put tick  (   ) where insoluble put cross (x).

  a b c
Solid Liquid Water Cooking oil
Chalk powder      



When solids dissolve in liquid they form a uniform mixture – solution.

Solid     + liquid                            Mixture

(solute)   (solvent)                         (Solution)

When two solid dissolves, it is said to be soluble.

When solid does not dissolve, it is insoluble.


Saturated solution

A solution that cannot take more of the solute at that particular temperature.


Small particles of solid that do not dissolve and remain floating in whole body of the liquid, when allowed for some time, they settle at the bottom of the container.


Factors that increase solubility

Activity 8

Discuss the factors that increase solubility.

(Temperature, surface area, stirring)



  1. Stains in clothes can be removed using correct solvents.


Activity 9

Which solvent can you suitably use to remove the following stains?

Stain                                                    Stain remover

  1. Grass stain
  2. Paint
  3. Blood
  4. Ink




Boiling point

Exp.To determine the boiling point of water.

Method:  Water, container, source of heat, thermometer.



Pour some water into a metallic container until it is half filled.  Heat the water and record the temperature at regular intervals of two minutes.



Record your observations in the table below.

Temperature (oC)

Time (minutes) 0 2 4 6 8 10 12


Plot a graph of temperature against time.



It is observed that on plotting the graph, the temperature rises with time until a maximum is reached and remains constant.  Here the graph levels off.  The temperature at which the graph levels off is the boiling point.









Bp – Temperature at which a liquid changes gaseous state.




Materials:  Container, pail, water, sell tape/masking tape.



Using a nail make three holes AB and C along a vertical line on the same side of the container.

Cover the holes with masking tape.

Fill the container with water.

Suddenly remove the masking tape and observe.

Record your observation.




It is observed that the water rushes out in jets.  The lowest jet goes further away from the container.  The jet from the top hole is closest to the container.


This shows that pressure at the bottom is highest and decreases upwards.  Hence pressure is liquids depend on depth.

Application of Pressure in Liquids


  1. Foundations of water tanks should be made stronger to withstand the high liquid pressure at
    the bottom.
  2. Walls of a dam and water tanks should be thicker towards the base to withstand increased



Put water in containers of different shapes.







The water takes the shape of the container.  Liquids have no definite shape.


Exp. To determine density of water

Materials:  Container, measuring cylinder, water, weighing balance.


Weigh out the container to determine its mass.  Put some water into the container until it is half full.  Weigh out to determine mass of container and water.

Pour the water into a measuring cylinder to determine the volume.

Calculate the mass water by subtracting mass of container from mass of water and container.

Calculate the density of water using the formula

Density    =        Mass



When liquids are mixed some will completely mix while others will not.  Those that mix completely form a homogenous solution and are said to be miscible.

Those that do not mix completely are said to be immiscible.  They form emulsions.  Emulsion is a mixture where droplets of one liquid appear floating in another liquid.  When allowed to settle, the small droplets join until the two liquids separate forming different layers.


An emulsifying agent  is a chemical that can be added to emulsions to prevent them from separating, e.g. soap can be used as an emulsifying agent for water and cooking oil since it attracts both of them.



Materials:  Water, Kerosene, methylated spirit, cooking oil, transparent containers stirrer


(a)  Pour some water in container until it is quarter full.  Add some methylated spirit until half
full. Stir and observe.

Repeat the experiment using cooking oil instead of methylated spirit.

(b)   Repeat (a) above using kerosene and cooking oil.

Record your observations in the table below (tick (   ) for miscible and cross (x) for Immiscible)

No.       Liquids Miscible Immiscible
1 Water + Methylated Spirit    
2 Water + Cooking Oil    
3 Water + Kerosene    
4 Kerosene + Cooking Oil    



Miscible Liquids

  1. Water + Methylated Spririt
  2. Kerosene methylated spirit

Immiscible Liquids

  1. Cooking Oil + Water
  2. Kerosene + Water





Oil secreted in our bodies attracts dirt on the surface of the skin.  To remove the oil and dirt one needs to wash with soap and water.  Soap is a suitable emulsifying agent.  To remove grease from your hands you need to wash with turpentine.


Experiment to demonstrate expansion of liquid

Materials:  Transparent container, water, capillary tube/straw (transparent), cork.


Fill a glass jar with water.  Fit in a transparent straw into a cork and cork the bottle tightly.  Heat the bottle gently spreading the flame on the sides to avoid heating directly on the same spot.

Observe what happens and record.


On corking the flask the water rises up the straw to a certain level.  On heating the glass flask, the level of water in the straw drops due to expansion of the flask.  After sometime the level starts rising up and goes beyond the initial level.

This shows that water expands on heating.

Different liquids expand at different rates.

Activity 10

Design an experiment to compare expansion rates of different liquids:

Water, cooking oil and engine oil


  1. Principle of expansion of liquids is used in thermometers. Mercury and alcohol are used to
    show temperature changes.



Some liquids flow easily when they are poured out while others do not.  Those that do not flow easily are said to be viscous.

Experiment to compare the viscosity of different liquids

Materials:  Smooth cardboard, droppers, piece of timber, water, cooking oil, engine oil and methylated spirit.


Put the cardboard on a slanting position by placing timber underneath one end.  Using droppers place about 5 drops of each of the liquids provided at the raised end of the cardboard at the same time.  Observe and record the liquid that reaches the bottom end earlier.


The liquids flow down at different rates.  Water flows faster than cooking oil.

Water methylated spirit, cooking oil and engine oil.

Increase in rate of flow slowest of the liquids.

Viscosity is the measure of resistance to flow that a liquid offers.

Activity 11

Design another experiment that can be used to show viscosity 0in liquids.


More viscous liquids can be used as lubricants e.g. grease and oil.  High viscous liquids are also used in hydraulic system e.g. in cranes.


Ability of a liquid to be drawn along a narrow tube.

When a glass with a narrow bore is dipped in a liquid, the level rises or drops depending on the type of liquid.


Materials:  Capillary tubes open ended at both sides, container, water and mercury.


Put water in a container.  Dip a capillary in the water and hold it upright observe.

Repeat using mercury instead of water.

Level of water rises                                                                           Level of mercury drops

in the capillary tube                                                                          in the capillary tube.

Activity 12

Describe another experiment which can be used to show capillarity.


  1. Spreading of ink over a blotting paper is due to capillary action.
  2. Kerosene rises up the weak of a lamp.
  3. The rise of water from the soil up the plants.
  4. Towels are used for drying our bodies after bathing.

Activity 13

Explain how each of the above is applications is as a result of capillary action.

Note:  Capillary action can cause dampness on walls of buildings.  How can this be avoided?

Surface Tension

It is observed that liquids form drops, water wets some surfaces but runs off others.  Some insects walk on water surfaces without sinking.

If a razor blade is placed carefully on water surface it floats.

This happens because the water surface behaves like stretched thin elastic skin.  This ‘Skin’ has a tendency to shrink to have a minimum surface area or an elastic membrane.  The force which causes the liquid surface to behave this way is called surface tension.

Particles of liquid are always attracting each other.  Those inside the liquid are attracted sideways and downwards.  This makes the surface to develop some tension.  This makes light objects like a razor blade float.


Materials:  Container, water, razor blade, soap solution.


Put some water in a container until it is almost full.  Place a razor blade slowly and carefully on the surface of the water observe.

Put two drops of soap solution on the surface of the water near the razor blade.  Observe.


The razor blade floats on the surface of water without sinking.  This demonstrates surface tension of water.

When soap solution is introduced, the razor blade sinks.  This is because the soap solution reduces the surface tension.

Factors affecting surface tension

  1. Impurities – they reduce surface tension e.g. detergents weaken the forces of attraction
    between liquid molecules.
  2. Temperature – Increasing temperature increases the energy of the particles, they move faster
    increasing the intermolecular distances hence weaken the forces of attraction between them.


  1. Water insects can rest of the surfaces of water.
  2. Mosquito larvae float on water. Oiling the surface breaks the surface tension and the larvae



Activity 14

  • (i) Put some water in a transparent container until it is half full.  Observe meniscus.

(ii)   Put mercury in a transparent container also and observe the shape of the meniscus.

  • (i) Put about five drops of water on the surface of a wooden table.

(ii)   Repeat (b) (i) using mercury.


(a)  Meniscus of water is concave in shape whereas that of mercury is convex in shape.

(b)  Drops of water spread of the surface of wooden table whereas mercury forms droplets which
do not spread.


In (a) the forces of attraction between water molecules is less than the forces of attraction between the water molecules and the walls of the container.  This makes the water tend  to move upwards at the walls making the meniscus appear concave.

In mercury, the forces of attraction between the particles are more than that between the mercury particles and the walls of the container.  This makes the mercury tend to move downwards at the walls making the meniscus appear convex.

In (b) water spreads on the surface because forces of attraction between and the wood particles is greater than that between the individual water particles.

The mercury forms droplets because the forces of attraction between its own particles are greater than that between the mercury and the wood particles. Forces of attraction between particles of the same substance are cohesion whereas that between particles of different substances is adhesion.


Cohesion reduce rate of evaporation.



Gases exert pressure.

Activity 15

(a)  The Crushing Can Experiment

Put a little water in a metallic container until the water boils.  Close the container immediately and allow it to cool.  Observe.

(b)  Fill a glass with water.  Cut a piece of paper to cover the mouth of the glass. Holding the paper with your hand, turn the glass upside down. Remove the hand holding the paper and


In activity 15

(a) thecan crashes on cooling because on driving out the air in it with the steam as the water boils, the pressure inside would be less than atmospheric pressure outside.  The pressure outside forces the container to crush.

In activity 15 (b) the atmospheric pressure acting on the paper upwards is able to hold the weight of the water in the glass.



Activity 15 (c)

Put two glass panes together.  Separate them.  Now et the panes and put them together.  Try to pull them apart.



It is observed that dry panes separate easily.  However when wet it is difficult to separate them.

On wetting the air between the panes is driven out.  The atmospheric pressure acting on the sides make it difficult to separate them.


  1. In drinking straws and pipettes. The air inside is sucked, thus pressure inside would be less
    than atmospheric pressure out.  This forces liquids up the straw or pipette.
  2. Before filling a fountain pen air inside is pushed out. Thus pressure outside the pen would be
    more than pressure inside hence ink is pushed into the pen.
  3. Sucking air in a siphon reduces pressure inside. Greater atmospheric pressure causes the
    liquid to flow provided the other end of the siphon is at a lower position than the level of the


Air has weight.

Activity 16

To show that air has weight.

Inflate two balloons with air and balance them on a beam balance as shown below.







Prick one of the balloons with a pin to deflate it.  Observe.

The beam balance tilts to show that the inflated balloon is heavier than the deflated one.

This shows that air has weight.


Air expands on heating and contracts on cooling.

Activity 17

Arrange the apparatus as shown above .heat the glass flask gently and observe.


On heating, air inside the flask expands and escapes through the straw.  Bubbles are observed at the mouth of the straw.

On cooling, air inside the flask condenses.  Pressure inside the flask would be less than pressure outside because some of the  air inside escaped.  This forces water up the straw.


  1. This heating and expanding of air can be used to explain formation of land breeze and sea



  • How land breeze is formed.
  • How sea breeze is formed




8.2.5  AIR

Composition of air

Air is made up of gases: Nitrogen, Carbon dioxide and inert gases.  The percentage composition is as given in the pie chart below;





Different components of air have different uses.

Activity 18 (In Groups)

Discuss the uses of

  • Oxygen
  • Carbon dioxide
  • Nitrogen
  • Inert gases (Helium, Argon, Neon


Activity 19

Design experiments to show that;

  • Oxygen is used in breathing
  • Oxygen is used in burning
  • Oxygen is used in germination


When two or more substances are put together and not chemically combined.  There are three types of mixtures.

  • Solid/solid mixtures
  • Solid/liquid mixtures
  • Liquid mixture.


Solid-Solid Mixtures

The following methods can be used to separate these mixtures.

  • Winnowing
  • Sieving
  • Picking
  • Use of magnets
  • Filtering
  • Sublimation

Activity 20

Discuss each of the above methods.

Solid-Liquid Mixtures

The following methods can be used;

  • Filtering
  • Decantation
  • Evaporation
  • Simple distillation

Activity 21

Discuss how each of the methods above are used.

Liquid-liquid mixtures

  • Fractional distillation
  • Chromatography
  • Use of separating funnel

Activity 22

Discuss how each of the methods  mentioned above are used to separate liquid mixtures.





9.2.1 Definition of terminologies

  1. Food – any substance, liquid or solid, that can be taken into the body in order to maintain life and growth.
  2. Food nutrients: elements found in foods which when absorbed into the body, perform different functions, e.g. carbohydrates, fats and oils, proteins, vitamins, mineral salts and water.
  3. A balanced diet: any meal which contains all the food nutrients required by the body
  4. Nutrition: processes in the body for making use of food.

The processes of nutrition

  • Eating the correct kinds and amounts of food the body needs
  • Digestion of foods so that the body can use the nutrients
  • Absorption of the nutrients into the bloodstream
  • Use of the individual nutrients by the cells for production of energy, maintenance and growth of cells, tissue and organs
  • Elimination of wastes
  1. Malnutrition: inadequate or excess intake of nutrients in the body
  1. Undernourishment: a form of malnutrition due to adequate nutrients in the body
  2. Over nourishment: a form of malnutrition as a result of excessive intake of certain nutrients

Causes of malnutrition

  1. Poverty: due to lack of financial resources to obtain adequate food, people end up suffering various nutritional deficiency diseases
  2. The body’s inability to utilize certain nutrients:  a condition in which a specific nutrient is not absorbed into the body. E.g. due to allergies
  3. Parasites:  presence of some parasites in the body deprives the host some essential nutrients e.g. infestation of worms and malaria parasites reduce the amount of iron and vitamin B12 leading to anaemia.
  4. Food taboo: food taboos, superstitions and religious beliefs may lead to the prohibition of eating certain foods.
  5. Ignorance: lack of information on healthy foods leading to consumption of less nutritious foods leading lack of proper nutrients to sustain body’s health and its ability to perform its functions.
  6. Natural calamities:  calamities such as floods, drought and war affect food production and distribution leading to food in availability
  7. Corruption: corrupt people grab land and hoard resources like relief food leading to low food production and distribution.
  8. Lifestyle: modern changes are lifestyle may lead to an increased intake of certain nutrients; this may lead to diseases such as obesity, gout, diabetes and hypertension.

9.2.2 Classification of foods and food nutrients

Foods are classified according to their food nutrients and functions in the body.

  1. Body-building foods

These are foods that contain proteins. Examples include meat, milk, legumes like beans etc.

  1. Energy-giving foods

These foods contain carbohydrate and fats and oils. Examples are starchy and sweet foods, oily and fatty foods like oily fish and nuts.

  1. Protective foods

These foods contain minerals and vitamins. They are mainly found in fruits and vegetables.



  • Proteins are made up of tiny building units known as amino-acids
  • Amino-acids are grouped into Essential amino acids which cannot be made by body. Non essential amino acids which can be made by body.
  • Proteins that contain all essential amino acids are known as complete or first class proteins. They are found in foods of animal origin like eggs, meat and milk. Soya bean is the only plant product that contains all essential amino acids.
  • Incomplete or second class proteins do not contain all essential amino acids. They are found in foods of plant origin like beans, peas, green grams and nuts.
  • In order to supply adequate proteins in the body, appropriate sources of proteins should be eaten.

Functions of proteins in the body

  • Body building which results in growth of body parts. Proteins are major component of boody muscles, brain, blood, enzymes, hormones and antibodies.
  • Repair of damaged tissues
  • Reproduction of heat and energy when there is inadequate supply of energy-giving foods
  • Prevents deficiency diseases called kwashiorkor which mainly affects children under the age of five years.


  • These foods are made up of carbon, hydrogen and oxygen molecules
  • Carbohydrates are broken down to produce energy.

Classification of carbohydrates

  1. Monosaccharide: glucose, fructose, galactose and mannose
  2. Disaccharides: sucrose, glycogen, cellulose (roughage)
  • Carbohydrates are absorbed into the body in form of monosaccharides so disaccharides and polysaccharides (starch and glycogen) must be broken down to monosaccharide before absorption
  • Cellulose is indigestible but is used as a dietary fibre


Functions of carbohydrates in the body

  • Provision of heat and energy. The body needs a steady supply of energy to function properly
  • Storage of glycogen. Glycogen stored in the liver and muscles is broken to provide energy when enough carbohydrates are not taken in. when adequate amounts of carbohydrates are taken to provide energy; the proteins in the body are spared. This allows proteins to be used for tissue building and repair and not provision of energy.
  • Roughage– (cellulose) aids in digestion and prevents constipation.

Fats and oils

  • These are food substances that are greasy to touch and insoluble in water
  • Fats and oils contain carbon hydrogen and oxygen
  • Fats are solid at room temperature and oils occur in liquid form at room temperature.

Functions of fats and oils

  • Energy provision
  • Fats and oils provide twice as much as energy as carbohydrates
  • Excess fats are stored in the body as fat deposits and are converted into energy when the body needs it
  • Body insulator– fats deposited under the skin acts as an insulator against cold.
  • Protection- fats deposits around internal organs protect them from physical injury.


  • Vitamins protect the body against diseases.
  • They are classified as follows
  1. water soluble vitamins all vitamin B (except B12) and vitamin C
  2. Fat- soluble vitamins. Include A,D,E,K


  • These are compounds which occur naturally in the earth
  • The most common minerals needed by the body are iron, calcium, phosphorus, sodium, chlorine, iodine and fluorine.

Functions of minerals in the body

  • Building and regulating body processes
  • Maintaining good health




Water is important because it:

  1. Forms about 70% of the weight.
  2. Forms a medium for all body reactions such as digestion and absorption.
  3. Is needed to lower body temperature when environmental temperature is too high. Water absorbs latent heat from the body to change into vapour which evaporates from the skin surface leaving a cooling effect.
  4. It constitutes fluids at major body joints( synovial fluid) which acts as a lubricant hence reducing friction during movement.
  5. It constitutes the medium for blood cells, tissue fluid and lymph. In this medium nutrients and gases such as carbon dioxide and oxygen are transported round the body.

Importance of fibre in the diet.

Fibre is also known as roughage. It arises from indigestible cellulose in plant materials. Sources of fibre are mainly vegetables and fruits. The function of fibre is to enhance movement of food along the alimentary canal, especially the large intestine. When there is insufficient in the diet, one is likely to suffer from constipation which can result in bowel cancer if it occurs frequently.

Nutrition for people with HIV and AIDS

With good nutrition people with HIV and AIDS can reduce the effects of HIV infection and regain goo health to some extent.

Usually, a person with HIV may feel that his/her health is not improving. He/she may experience the following.

  1. Poor appetite.
  2. Poor digestion of food.
  3. Due to poor digestion he/she passes out stools and urine that show that he/she is not well.
  4. Lack of deep, restful sleep.


  1. a) How to help the person to regain appetite

The person can improve his/her appetite by:

  1. Using chilies and vinegar. They can create a hunger of food.
  2. Using ginger and coriander. Ginger helps in digestion of food. It prevents food form staying undigested in the digestive system is too long. When food overstays due to slow digestion, we experience a feeling of being full, passing of gas and diarrhea. Ginger helps to correct this. Coriander helps to increase appetite. It also helps to control fungi and bacteria. Ginger and coriander give a pleasant taste.
  1. b) How to help the person have a good digestion.

The person should when hungry and not necessarily mealtime.

  1. Eat wholesome foods. These include fresh vegetables and fruits. They should also use unrefined maize or wheat flour. The maize milled without removing the husks is better than sifted flour- similarly brown bread is better than white bread.
  2. Eat slowly and mix a lot of saliva with each mouthful. Eating too fast is not good for the digestive process and the immune system. Digestion begins in the mouth. Chewing well assists digestion in the stomach and small intestines. It also assists the immune system to work well and prevent HIV infection from spreading.
  3. Include fruits like paw paw and pineapple in the diet. These fruits help in digestion and improve appetite. Good digestion and absorption help immune system to fight diseases.
  4. Eat digestive spices (herbs) with the food. These include coriander, ginger, cloves, cinnamon curry powder and turmeric. They help in digestion and increase appetite. They also make the food tasty, act like medicine and kill bacteria.
  1. c) How to help the large intestine to deal with food.

It is common for HIV infected people to experience diarrhea over a long period of time. This shows that there is a problem when food passes through the large intestines. To improve the work of the large intestines we can do the following:

  1. Feed them a diet rich in such as whole meal maize flour, whole wheat brown bread, oat meal, millet, cabbage, cowpeas leaves, carrots, raw garlic, green bananas, pears, apples, plums, rinds of citrus fruits (lemons, oranges and grapefruit), beets and lady’s fingers (okra).
  2. Give them fermented milk products and yoghurt. They make the environment in the intestine unsuitable for the increase of HIV.
  3. Give raw garlic. This stops increasing of HIV and kills other germs.
  4. Give cabbage when raw cabbage juice or fermented cabbage juice.
  5. Give coconut oil or milk or use it for cooking instead of cooking fat.
  1. d) How to choose foods that make their excretory system work well.

They should:

  1. Have fresh foods, salads and fruits.
  2. Have less fat, less salt and more fibre.
  3. Have less meat and more plant protein. He/she may include eggs and milk in the diet.
  4. Eat small quantities of meals regularly.
  5. Drink a lot of water (8 glasses per day).
  6. Avoid alcohol.


  • Balanced Diet

A balanced diet comprises nutrients needed by the body in the right quantities. The nutrients include carbohydrates, proteins, fats and oils, vitamins, minerals, water and fibre. It is important to ensure that one eats a variety of foods in every meal. This enhances obtaining of a variety of nutrients by the body. There should be no preference for certain foods only at the expense of others. Having a balanced diet can be made up cheap using foods that are in season.

9.2.5 Common nutritional disorders

These are caused by an inadequate or excessive intake of a given food nutrient. They can also be caused by poor absorption and use of food nutrients.

  1. Kwashiorkor

A protein deficiency disease

Occurs when a child stops breast feeding at an early age and is fed foods lacking in proteins.

Signs and symptoms

  • Selling of the stomach, face, hands and feet. A condition known as Oedema.
  • Hair is scanty, thin, brownish and looks straight
  • Child looks dull and inactive
  • Retarded growth
  • In severe cases, skin peels off patches leaving wounds. Brain development is affected.


  1. Marasmus
  • A deficiency disease which is caused by inadequate intake all food nutrients over o period.
  • Occur in both children and adults, especially during drought and famine. May also be as result of a chronic illness like HIV/AIDS, Tuberculosis and Cancer.

Signs and symptoms

  • Extreme loss of weight. One is skinny and may weigh half the expected weight.
  • There is no fat under the skin, especially around the upper part of arms, the thighs, buttocks and stomach which are wrinkled
  • The child looks like an elderly person because the face is wrinkled
  • The ribs can be seen and the child is generally alert or anxious
  • The hair may look normal, but the head will look big in comparison to the rest of the body
  • The child is weak and growth is retarded
  1. Scurvy

Deficiency disease caused by lack of vitamin C in the diet

Symptoms of scurvy

  • Weak blood capillaries which break easily
  • Bleeding gums
  • Anaemia (vitamin C is important for absorption of iron in the body)
  • Unhealthy skin
  • Wounds that take long to heal
  • General body weakness
  1. Iron- deficiency anaemia
  • Occurs as a result of lack of iron in the body.
  • Iron and proteins are important for the formation of red blood cells and haemoglobin which carries oxygen to the body organs
  • Usually, babies are born with enough iron to last them the first six months of life
  • Teenage girls and women of child bearing age should eat more iron rich- foods since they are more likely to be anaemic than other groups. They lose blood during menstruation and child birth.
  • Chronic malaria and hookworms’ infestation can also lead to anaemia.

Signs and symptoms

  • Paleness of tongue, gums and the inner side of the eyelids
  • Weakens and dizziness which result in fainting
  • Sometimes the heartbeat is pronounced
  • Shortness of breath occurs when doing tasks which under normal circumstances would not cause it
  1. Rickets
  • Caused by lack of vitamin D in the body resulting to poor formation of bones
  • Vitamin D is necessary for the proper use of calcium and phosphorus in bone formation

Signs and symptoms

  • Weak bones
  • Poor development of teeth
  • Knock-knees or bowlegs
  1. Osteomalcia
  • This is rickets in adults
  • Caused by inadequate intake of calcium, phosphorus and vitamin D in the diet, causing the bones to become weak and fragile
  • Osteomalcia is common among women who have frequent birth

Signs and symptoms

  • Fragile bones that fracture easily
  • Deformity of the pelvis as a result of weakened pelvic bones
  • Pain in lower back. Legs and pelvis
  • Uncontrollable twitching of muscles, especially of the face and hands.
  1. Beriberi
  • Caused by lack of thiamin (vitamin B1)
  • Common among people whose diets consists mainly of highly polished or refined cereal grains
  • May occur in form of ‘wet’ or ‘dry’ beriberi ion adults. In early stages the symptoms of both are same.
  • Children under six months suffer from infantile beriberi

Signs and symptoms

  • Fluids are retained in the body tissues (oedema)
  • Pronounced and rapid heartbeat
  • Chest pains
  • Reduction in amount of urine passed due to the retention of fluid in the body.

Signs and symptoms of dry beriberi

  • Fluids are not retained in the body tissues
  • Weakness and wasting of muscles
  • Numbers and feeling of pin pricks on the feet arms
  • Difficulty in walking and rising from a squatting position

Infantile beriberi

Affect children who receive inadequate amounts of thiamin from breast milk, due to deficiency of the vitamin in the mothers’ body.

Signs and symptoms

  • Whining and weakness
  • Diarrhea, loss of weight and vomiting
  • Development of Marasmus, oedema and fits if the disease progresses
  1. Pellagra

Caused by lack of nicotinic acid in the diet

Signs and symptoms

  • Loss of strength
  • General weakness
  • Mental depression
  • Rough skin and reddish rashes
  • Diarrhea
  • Checked growth in children
  • Possible insanity
  1. Goitre

Disease caused by a deficiency of iodine. It is characterized by the swelling of the thyroid gland situated at the lower part of the neck

Signs and symptoms

  • Enlargement of the thyroid gland
  • Irritability
  • Tiredness
  • Weight loss
  • Change of eating habits
  1. Keratomalacia
  • Deficiency disease caused by lack of vitamin A
  • Usually begins with night blindness and if not corrected, leads to total blindness

Signs and symptoms

  • Night blindness (difficulty in adjusting from good lighting to dim light at night)
  • Drying and hardening of the fluids of the eye come out and cause blindness
  • Mouth becomes dry and cracked
  • Skin becomes dry and scaly


9.2.6 Nutrition for special groups

Meals for  children

  • Give a balanced diet rich in calcium and phosphorous for strong bones and enough energy foods.
  • Provide variety foods to allow choice.
  • Provide crunchy and crispy foods to exercise teeth and jaw bone.
  • Serve small quantities in small plates or bowls.
  • Present attractively
  • Serve at regular intervals and punctually.
  • Food should not be highly seasoned, flavoured or sweetened.
  • Avoid giving snack in between meal other than milk and fruits
  • Give enough fluid to aid digestion and replace fluids lost during play.
  • Give vegetables and fruit to provide roughage which prevents constipation.

Meals for lactating mother  (breast feeding /nursing mother)


Points to consider:

  • The meal should be well balanced
  • Provide enough proteins iron, carbohydrates, fats and vitamins A and C.
  • Give adequate calcium for strong bone and teeth.
  • Provide plenty of fluids to increase milk production
  • Serve the attractively
  • Serve the meals punctually and at regular intervals to avoid monotony.
  • The meals should be well flavoured to improve the appetite.
  • Mix different foods for strict vegetarian to ensure a complete protein supply.
  • Provide appropriate amount of vegetables fat and oil.
  • For lacto – vegetarians make a good use of animal products to provide a complete protein supply.


Definition of food hygiene

This refers to health practices that safeguard against food contamination. Kitchen hygiene refers to cleanliness of surfaces, equipment and proper disposal of refuse.


Kitchen hygiene practices


  1. Keep kitchen clean always that is free of spilt foods crumbs and scarabs which may attract household pests.
  2. Keep kitchen utensils clean at all times.
  3. Large bins outside the house should have tight fittings kids, positioned away from windows and disinfected regularly.
  4. Kitchen clothes must be washed daily and boiled to kill germs
  5. Keep storage equipment such as refrigerators kitchen stores etc clean at all times
  6. Kitchen refuse bin should lined before user and must have a tight fitting lid. should be emptied daily and washed.
  7. Kitchen work surfaces should be cleaned appropriately with warm water and detergent.
  8. Clean water should be used in food preparation and washing the utensils.
  9. DO not reheat food more than once to prevent food poisoning.
  10. Cool left over foods and store immediately in clean containers and in cool/cold places to prevent poisoning.

Personal Hygiene In Relation To Food Hygiene

  1. Wear protective clothing to prevent contaminants from outdoor clothing coming into contact with food, surfaces and equipment.
  2. Wash hands with warm soapy water and dry before handling food especially after visiting the toilet, handling money activities which bring hands into contact with mouth should be avoided.
  3. People suffering from water borne diseases should not handle food during preparation, cooking or serving people.

9.2.8 Table manners

-These are table manners which should be observed at all times

  • Do not talk with the food in the mouth
  • Pass the food to other people after serving yourself
  • Watch and copy on the use of cutlery if you don’t know how to use them
  • Avoid overstretching to reach out for salt and other condiments but instead request for them
  • Chew the food with the mouth closed
  • Keep to the pace of others while eating
  • Avoid serious discussing during meals
  • Use low tone to communicate at the table
  • Do not place elbows on the table
  • Cover the nose and mouth when sneezing or coughing
  • Avoid clearing the throat loudly or spitting on the floor
  • Do not handle or comb the hair during meal time
  • Use toothpicks not fingers to pick the teeth and a clean handkerchief for the nose


9.2.9 Food Spoilage and Poisoning

  1. Food spoilage

Refers to the deterioration of food resulting in the food becoming unfit for human consumption

  1. Causes of food spoilage


  • Oxidation of chemicals present in fats and fatty foods
  • Chemicals present in pesticides and herbicides sprayed on fruits and vegetables.
  • Chemicals present in food containers, wrapping and packets.
  • Action of enzyme in fruits that make them overripe and finally rot or natural poisons found in some food.
  • Rancidity that is decomposition of fats.
  • Bacteria/fungi that contaminate s poorly stored food.
  • Mould yeast.
  1. Food poisoning

It is an illness caused by consumption of spoilt food containing toxins from chemical poisons, natural poisons and harmful micro-organisms which react with the body.


Causes of food poisoning

  • Chemical contamination
  • Bacterial contamination
  • Natural poisons

NB:  all these produce toxins which poison the body.


Signs and symptoms of food poisoning

  • Severe abdominal pains
  • Diarrhea
  • Dizziness
  • Fever/headaches
  • General body weakness
  • Vomiting which is severe.


        Prevention of food poisoning and spoilage

  • Observe hygiene when handling food.
  • Buy food which is not expired by observing the expiry date.
  • Wash fruits and vegetables thoroughly using boiled cooled water.
  • Do not store chemicals near food
  • Dry cereals completely before storing.
  • Cook food well to kill germs/bacteria
  • Avoid eating in dirty restaurants or suspicious places
  • Buy food from clean markets and vendors.
  • Avoid reheating food more than once.

9.2.10  Food Preservation

Food is made is made up of living materials, which are subject to gradual process of decay and deterioration or change.  This may be caused by any or combinations of the following:

  1. Chemical changes in the living parts of the food facilitated by the action by the cell enzymes.
  2. Micro-organism that get into the from outside such as bacteria, yeast and moulds.
  3. Pests such as weevils and rats which attack food destroy it.

Definition of Food Preservation

Giving food a treatment in order to either slow down or stop decay and deterioration

Reasons for preservation:

  • To destroy the micro-organisms, for example, by applying heat]
  • To render food undesirable for the survival of micro-organisms by, for example, by freezing.
  • To stop the enzyme or chemical action, by drying or by heating.

Advantages of Food Preservation

  • preservation is necessary so that it can be used when out of season
  • For proper storage and proper use
  • For easier transport and convenience
  • To avoid Wastage
  • Some method of food after preservation produce variety i.e. certain type of food can be used differently.


Disadvantages of Food Preservation

  • Some type of vitamins may be destroyed due to preservation
  • Can cause food poisoning if poorly preserved.
  • Some chemical preservatives alter the natural taste of food.
  • Some changes may be stopped by food preservations e.g. Preserved mild cannot

Methods of preserving food

  • Application of heat
  • Removal of water
  • Exclusion oxygen
  • Freezing
  • Adding sugar, salt, acids and chemical preservations.

Traditional Methods of preserving Food

Drying or Dehydration:

Drying is one of the oldest method and widely used.  Micro-organism cannot grow on dried foods.

It also concentrates the soluble ingredients in food.

Complete drying destroys neither enzymes nor the harmful organisms.

It only inactivates them.

Aflatoxins develop in cereals when stored in damp conditions, which causes serious poisoning.

General rules for drying foods

  1. Use clean hands, equipment and water
  2. b) Use fresh food, which is in good condition
  3. c) For sun drying, cover the food with mesh or neeting to prevent dust, flies, insects or pests from contaminating.
  4. d) Do not dry food directly on the ground. Spread them on a clean surface or material.
  5. e) Store dried food in tightly containers, away from pests, dirt and moisture.

The following points should be observed when preserving vegetables

  • Wash them thoroughly in clean water.
  • Shell or prepare vegetables as for cooking.
  • Blanch the vegetables before drying to stop the action of enzymes, so that food will not spoil during drying.
  • Blanching kills bacteria and helps in retention of vitamins, minerals and the colour of vegetable.
  • They are then cooled in cold iced water for an equal time as that of boiling the water.
  • Drain the vegetables
  • Spread the vegetables on a tray or mat so that they quickly dry.
  • Cover the tray or mat with a piece of netting, muslin cloth or thin wire netting.
  • Place the tray under direct sunlight if possible.
  • Turn the food regularly so that it dries quickly.
  • Test the food for dryness by squeezing it in the hand. It should be crispy and dry.

Store in airtight containers

Drying root vegetables

  • peel the vegetable and cut in to small pieces
  • spread the pieces on a wire tray or canvas
  • Cover with another wire or canvas to keep the birds away.
  • Leave in the sun but turn occasionally until they dry.

Drying Cereals or pulses

  • Harvest them when the quite dry
  • Complete drying them by spreading them on a mat in the sum.
  • Treat and store appropriately.

Drying Meat fish

  • Cut meat into thin strips, clean fish as for cooking and cut it open.
  • Dry on a tray covered with a thin cloth netting, or thin wire mesh. Meat and fish can be hanged on a string to dry.
  • Place the tray in a such a position that no animal or insect can reach it , as they will be attracted to the smell.
  • Meat and fish canal so be dried in a wire cage which is covered by a lid.

Modern Methods of Preserving Food

  1. Solar and Mechanical Drying

Drying food is by solar (sun) drying and mechanical drying (dehydration)

(a)  Sun (Solar) drying

In sun solar drying, the sun provides the heat to dry whereas the    wind currents drive away the moisture-laden air from the food.

This may take several day and is practical where sun is in abundance.


(b) Dehydration (mechanical drying)

This is done using machines.  The heat is artificially produced.

Temperature and humidity are controlled.    A mechanical drying machine has fans, which cause air to move, carrying away moisture from the food.


(c)  Improvised drying and smoking

It is done in a big drum which is specifically prepared for that purpose.

Fire is made at the bottom part.  The rising smoke and hot air dry and smoke the food quickly.

Milk and eggs are preserved in powder form by drying.


  1. Salting

A high concentration of salt kills micro-organisms and prevents the action of enzymes.

  1. 3. Use of Vinegar

Food preserved in vinegar can keep for a long time and will have an interesting flavor.

Vinegar is often combined with salt.

  1. Use of Sugar

The action of enzymes is also impaired by a high concentration of sugar.

Fruits left whole or cut can be preserved this way

  1. Use of Heat

(a)  Bacteria, yeast, moulds and natural enzymes are destroyed









10.1 Specific objectives

At the end of the topic, the learner should be able to;

  • define environment
  • describe the component of environment
  • observe different habits
  • describe different types of habitats
  • explain interdependence between organisms
  • construct food chain and food web
  • explain how various organisms are adapted to their habitats
  • state factors that affect population growth
  • define pollution
  • describe different types of pollution and their causes
  • state effects of pollution on environment
  • describe control measures of pollution
  • describe measures of conserving soil, water, plants and animal life
  • Describe ways of handling waste.

10.2.0 Content 

10.2.1 Definition of Environment

It refers to the totality of conditions and circumstances that surround an organism.

It includes the external conditions, stimuli and resources with which an organism interacts and which affects its survival, development and population.

10.2.1 Components of Environment

The environment includes the non-living physical aspects of the place where an organism lives, and the living things that may affect the organisms.

The non- living aspects of the environment make the abiotic environment while the living components make the biotic environment.

The Biotic environment

These include living organisms both plants and animals.  It is the living component of the environment.

The living organisms interact with each other in a number of ways as follows:-

(a)  Competition

This is the interaction between members of the same population or of two or more populations that share the same resources, often present in limited supply.

Competition is greatest among organisms that have similar requirements or life styles.

Plants always compete with each other over sunlightand water.

Herbivores may compete for vegetation while carnivorous will compete for prey.

(b) Predation

This is an interaction between organisms where one organism the predator feeds on another living organism the prey.

The feeding of living organism can be by animals eating plants, animals eating other animals or plants eating animals.

An example of predation is a cheetah feeding on gazelle.

(c)   Symbiosis

This is an intimate association between two or more organisms of different species.

Parasitism, Mutualism and Commensalism are all examples of symbiotic interactions.

        Parasitism–   This is the interaction between two organisms in which only one, the parasite

Benefits and the other, the host is harmed.

  • For example fleas feed and live on a dog which is unwilling host.

Mutualism – This is an association which is beneficial to both and no harm is inflicted on either of the organisms.

  • A good example of mutualism is seen in lichens.

This is an association between a fungus and an Algae.  The algae is provided with a means of

attachment and obtain water, carbon dioxide and minerals salts.

The fungus in turn obtain oxygen and carbohydrates made by the Algae through



This is an association between two organisms where only one benefits and the other is

neither harmed nor benefits.

Some examples include Bryophytes and the trees on which they grow or a tree and the birds

nest on it.  The tree is not affected


The Abiotic Environment

The following are abiotic factions that affect an organism:-

(i)  Temperature

It affects the distribution of organism since reactions within the cells occur within a given temperature range.


(ii)  Air

It is needed for respiration; Note air contains Oxygen.

(iii) Water

Plants use water during photosynthesis.

Water is also used as a coolant, solvent and a habitat for aquatic life such as fish.

(iv) Humidity

This is the amount of water vapor in the atmosphere.

It affects the rate of evaporation.

(v) Topography

This refers to the gradients or slope of the land.

It influences service run-off, hence important in the formation of water masses like rivers and lakes.

(vi)  Soil PH

Soil PH refers to the acidity or alkalinity of the soil.

It play a big role in the availability of nutrients hence determines the type of organisms to inhabit a given area.


(vii) Sunlight

It is necessary during photosynthesis

Other factors include the Hydrological cycle, Atmospheric pressure, Wind and Ocean currents.

  • Types of habitats

A habitat is defined as the specific place where an organism lives.

For example all the organism living in a freshwater bond

The following area examples of habitats-:

(i)  Terrestrial (Land) habitat

(ii)  Aquatic habitat freshwater, salty water or swampy habitat.

The characteristics of organisms in each of the habitats are influenced by the existing conditions which may be physical or chemical.


10.2.4 Interdependence

This is a situation whereby organisms depend on each other for survival.

The organisms can be plants or animals.

Plants and animals depend on each other in different ways.

Some plants depend on other plants while some animals depend on other animals.


Interdependence between plants

(i) Plants providing support

Plants that have weak stems to grow upwards and get sufficient sunlight get support from plants with strong stems.

This is seen in climbers and creepers.

(ii) Plants providing a habitat for others

This is seen in the mistletoe.

This is a parasitic plant which lives on another plant to get food and shelter.

When you observe the stem and barks of trees especially during the rainy seasons you will also see lichens and moss.


(iii) Plants providing shade

Some plants depend on each other to conserve water.

Some small plants loose water easily because they are directly exposed to sunlight.

To avoid this, they grow under big trees which provide shade for them by their dense canopies.

This is clearly seen in forests.



Interdependence between plants and animals

Plants and animals depend on each other in the following ways-:

(i)  Food and Nutrients

Whereas green plants can make their own food during photosynthesis.

Animals feed on plants directly or indirectly.

The animals which feed on green plants are call herbivores.

Examples of herbivores are Antelopes, Elephants, Cattle and Zebras.

Some animals eat the animals which feed on plants.  Example of such animals are Lions feeding on herbivores like lizards.

These animals are called carnivores flesh eaters.

Some plants also feed on animals especially insects.

Such plants are called insectivorous plants.

Examples are the Pitcher plant, Venus fly trap and Sundew.

Animals depend on plants from shelter and security.  For squirrels to escape from danger, they climb plants.

(ii) Pollination and dispersal

Another observation where plants are seen to depend on animals in pollination and fruit and seed dispersal.

Birds and insects carry pollen grains from one flower to another in the process of searching for nectar in flowers. This promotes pollination and hence reproduction in plants.

Animals help in dispersing seeds somewhere away from parent plant.

At times, the seeds stick to the body of the animal and are dropped far away.

When such seeds find conducive conditions they germinate and grow into adult plants.

(iii)  Medicines

Human beings also depend on plants to get a number of medicines.

The medicines are used to treat diseases.

Some plants are used as spices in food preparation like onions, pepper, garlic and cloves.


Interdependence between animals

This is seen in some interrelation ships like predator – prey relationship.

If a carnivore like a lion feeds on a herbivore like a zebra, the lion population in that particular environment will depend on the abundance of the prey i.e. the herbivores.

In the savannah grassland, the scavengers like vultures, hyenas and jackals wait for the kill made by the supper predators like the lions who are more skillful hunters.

They then scavenge for the remains and this way they depend on the super predators like lion, cheetah and leopards.


10.2.5 Adaption of organisms to their habitats

Adaption is development of some features that make a group of organisms better suited to live and reproduce in their environment.


Water availability is the most important environmental factor that determines the natural distribution and abundance of plants in various surroundings of the earth.

Each species of plants possesses various adoptions that enable it to cope with the level of water availability in its natural environment.

Based on these adoptions plants are classified into the following four groups:-


  1. Xerophytes

Plants that are able to live and survive in very dry areas are called Xerophytes.

Examples of xerophytes are Acacia, Pear cactus, Aloe, Sisal and some desert shrubs.

The major problem of plants living in very dry places is the scarcity of water.

These plants have developed structural Physiological and behavioral adaptations that can enable them to conserve the little water they get.

The following are some adaptations-:

(i)  Some plants have developed extremely long roots that go very deep in search for underground water.  An example of these plants is the acacia plant.

(ii)  Most plants have leaves which are reduced in size needle-like in shape or which have been reduced to spines or thorns.

This reduces the surface area of the leaf and hence reduces water loss by transpiration.

The spines also protect the plants from being fed on by animals.

(iii)  Some desert plants are deciduous plants.

They shed their leaves when water is in short supply.  This reduces transpiration of water.

(iv) Some plants have their leaves covered with a thick waxy cuticle which further reduces loss of water by evaporation

(v) A plant like cactus has no leaves but has a thick fleshy green stem for photosynthesis.

The thick stem does not allow much water to be lost by evaporation.

The stems are also swollen with stored water.

  1. Hydrophytes

Plants that are able to live in water or very wet conditions like swamps are called


The major problem of hydrophytes is how to get enough oxygen and get rid of excess water.

Examples of hydrophytes are water hyacinth, water lily, duck weed, rice and buttercups.

Hydrophytes have the following adaptations;

(i)  Many have large flat leaves to increase the surface area so that they can float easily for example the water lily.

(ii) They have thin cuticle covering the leaf surface to allow for faster water loss.

(iii) They have an increased number of stomata.

Most of stomata are on the upper surface and remain open most of the time.

This is to allow for absorption of gases and light for photosynthesis and increase water loss through transpiration.

(iv) Their leaves have air sacs which also enable the plants to float.

(v)  Their stems are flexible so that they can sway with the water currents without being


(vi) Some hydrophytes have small roots to reduce the surface area for water absorption.

The roots are also feathery to support and balance the plant as it floats in water.

Most hydrophytes have their flowers raised above the water for visibility and to allow cross-pollination by small insects.

  1. Mesophyte

These are plants that live in well-watered soils or areas with optimum (normal) conditions.

Mesophytes have the following adaptions:

(i)  Their leaves are relatively broad with a thin lamina containing large numbers of stomata on both sides.

This offers a large surface area for transpiration.

(ii)  The roots are usually shallow since water is often present close to the soil surface.

(iii)  They have a thick cuticle which prevents water loss through transpiration.

(iv) Most of their stomata are located on the lower surface of leaves, which is shielded from direct sunlight and wind.

(v)  Mesophytes that are found in dense forests face a problem of obtaining enough sunlight.  Trees grow very tall in an attempt to get sunshine.

–  Other plants called Lianas have coiled woody stems that climb to the top the forest in an attempt to obtain sunlight.

–  Others called Epiphytes grow perched on other trees through not obtaining nutrition from them.  This enables them to obtain sunlight

Examples of epiphytes are them Mistletoe, Certam ferns and the Carnivorous pitcher plant.

  1. Halophytes

These are plants that live in areas of high salinity such as salt marshes and estuaries.

They have the following adaptations;

(i) Some accumulate salt actively in their calls.   This increases the osmotic pressure in the cells

enabling the plants to take up water by OSMOSIS.

(ii)  Some have salt glands in their leaves which excrete excess salts.

(iii)  Some have succulent tissues where they store water which they absorb when the salt content is relatively low.

(iv)  Some have large air spaces in stems and leaves which accumulate gases making them available to the submerged parts.  The gases also provide buoyancy to submerged parts.

(v) Some halophytes e.g. Red Mangroves have some have slit-like roots which anchor them firmly to the ground and bind the mud.   This protects them from being washed away by waves and tides.

(vi)  Some like the white mangroves have breathing roots.  These grow vertically upwards from the main root system into the air.

They have lenticels through which air enters.  They help to supply the oxygen required for respiration to the submerged parts of the root system.



Adaption to grassland ecosystem

The African tropical grassland also called the savannah occupies about half the area of East Africa.

The savannah is the home of a large variety of animals both herbivores and Carnivores.

Some of the herbivores are grazers that feed on grass.  They are mainly found in open grassland and include Antelopes, Wildebeests and zebras.

Others are browsers that feed on leaves and small branches of trees.

These are found mainly in wooded areas and include the Giraffes, Rhinoceros and elephants.

The Carnivores include the Lions, Leopards, Hyenas and Vultures.

The herbivores of the savannah usually adopt a body colour which matches that of the surroundings.

For example, the antelopes which are mainly found in open grassland have a brownish colour more or less the color dry grass.

The browsers like giraffes have a spotted green color, move or less similar to that of the trees.

This helps them to camouflage in the background environment an important way of hinding from predators.

In addition most of the herbivores can run very swiftly, which help them to escape from their carnivorous predators.

Carnivorous have the following adaptations:-

(i)  They have a very good sense of smell.

(ii) They have good eye sight

(iii)  They are good at hearing

(iv)  Their body color blends with the environment especially for those in the savannah.

(v)  They have powerful legs and muscles for faster movement.

(vi)  They have sharp and strong claws.

(vii) They have powerful and well-differentiated teeth.


Adaption of birds

Birds have a number of adaptive features such as beaks and feet.

Birds also have special features, for example wings for flying.

Flesh eaters or birds of prey.

Examples are eagles, hawks, kites and vultures.

These birds are hunters.  They catch and eat chicken, rats, mice, fish among others.

They have the following adaptations

(i) They have strong and sharp curved or hooked beaks, suitable for killing prey and

eating flesh.

(ii)  They have long toes and strong curved nails or talons for gripping their prey.

(iii)  They also have powerful eyesight to enable them spot their even from very far.


The following are adaptations of the body of a bird for flight:-

(i) They have strong and sharp curved or hooked beaks suitable for killing prey and  tearing flesh.

(ii)  They have long toes and strong curved nails or talons for gripping their prey.

(iii)  They also have powerful eyesight to enable them spot their prey even from very far.

The following are the adaptations of the body of a bird for flight:-

(i) Streamlined body shape which allows it to move quickly with less resistance to

friction from the air.

(ii) The have hollow bones to reduce weight and the backbone is fused to give it ridity.

(iii)  The head is small and is attached to a long neck.  This allows the bird to move its     head quickly and easily.

(iv) They have a reel for attachment to its powerful and strong pectoral muscles which

are used for moving the wings.

(iv)  It has nictitating membrane which covers the eye and protects it against moving air.

(v)  It has no pinna to obstruct the flow of air.


Adaptations in fish

A fish has the following features:-

  • It has a streamlined body which helps it to move easily in water.
  • A slippery skin which helps to reduce friction as it swims.
  • The body is covered with scales for protection.
  • The body color of a fish from above is generally dark and silvery white from below

This color combination makes it hard for the enemies to see the fish.

  • It has got gills adapted for breathing while in water.
  • Fish has a lateral line which helps it to sense any danger that may arise.
  • It has got different types of fins which helps it to move and maintain balance in


  • Factors affecting population growth

10.2.7 Pollution

  • Define pollution
  • Causes ,effects and control
  • Pollution of:
  • Water
  • Air
  • Soil

Sound pollution

  • Conservation of soil , water , plants and animals

Most countries, soil is commonly subjected to erosion and degradation by people through bad farming other activities.

Soil needs to be conserved to improve crop yields. Also vegetation needs to be planted to prevent desertification.

Soil can be degraded by water by water and wind erosion.

Soil erosion by water and can be prevented in the following ways:-

  • Ploughing following containers and making terraces.
  • Making gabions where there are gullies to prevent further loss of soil.
  • Preventing of cutting vegetation that holds the soil together. This reduces soil erosion.
  • Deforestation must be discouraged as much as possible and where a few trees are cut more be planted.

Soil degradation

Degradation refers to change of soil, ph, structure and texture.

Such soils fail to support vegetation crop tied decreases and makes farmers use a lot of agrochemicals, biocides and fertilizers which continue to pollute soil and water.

One of the major causes of soil degradation is over cultivation potential areas. Due to population pressure in the medium and high potential areas the land is over cultivated thereby exhausting the soil. Farmers are therefore forced to usefertilizers and other agrochemicals to improve the yield. These chemicals with changes the soil ph and texture.The following are ways through which degradation of soil can be avoided:-

  • By the farmers using natural composite manure.
  • Soil can be allowed to rest
  • Soil degradation

10.2. 9 Handling waste

Making good use of waste materials

  1. Coffee husks
  • Until recently coffee husks were being thrown away as a waste product.
  • It has been realized that coffee husks can be compressed and made into coal
  • Kahawa coal is available in the market and can be used as a substitute for coal.
  1. Cow dung:-
  • Cow dung is a waste product generated in the forms and ranches.
  • In traditional societies cow dung had been put into many uses
  • When mixed with mud cow dung to pastor the walls and floors of rational houses.
  • It can also be used as rich manure and help farmers to increase soil fertility
  • It can be dried and used as fuel for cooking.
  • Nearly 150 – 400 million tons of dung is burnt every year throughout the third world countries energy purposes.
  • Today cow dung and other dung’s is used as biogas which can be used in gas stoves to generate heat for cooking in a turbine to generate electricity.
  • Biogas is a mixture of methane and carbon dioxide gases.
  1. Ashes
  • Ash is obtained as a result of complete combustion of wood and dried cow dung etc.
  • Ash is rich in potassium salts which are a nutrient in the soil.
  • Ash is also used as a detergent for cleaning utensils.
  • Small scale farmers can use ash for food grain preservation.
  • Although some chemical can be used for this purpose, they are expensive.
  • Ash has no harmful effects on quality and usability of food grants.

Recycling of materials


Recycling refers to the conversation of waste into reusable material.

  1. Dirty water

The water which we use should be clean and free from impurities and microbes.


It is important to treat dirty water by physical, chemical and biological means to it safe for human use.

Domestic and sewage. Wastes should be suitably treated before being realized into water.

In primary treatment the sewage waste is passed through a series of screens to remove large particles and then through grinding mechanism.

The sewage is now passed through several settling chamber s to remove heavy gift and other suspended solids

Thus primary treatment is by physical process like sedimentation, floating and filtration.

In secondary treatment the sewage obtained after primary treatment is pumped into aeration tank where it is mixed with air and sludge which contains bacterial and algae.

The bacteria decomposes and consume the organic matter where as algae provides oxygen for the bacteria.

In tertiary treatment even after microbial decomposition the water is unfit for drinking due to the presence of pathogenic,bacterial, protozoa and harmful chemical

Tertiary treatment is done by use of urine.

The principals of purification of sewage are modified according to the discharged into it.

In factories water is used as a coolant, this must be used over and over again to cut down on operational cost.

Water is also used as a solvent in some cases well as for washing and other purposes.

If this re-cycling is not the factories may discharge their industrial effluents into rivers causing water pollution.

The waste water from the factories is prevented in what is known as high rate. Rate biofitters and then released to go into the connectional sewage treatment plant and goes the same process describe above.

The treatment effluent from the sewage can now be used for industrial purposes or released to flow as clean water down the stream, dam or river.


  1. Waste paper

Paper manufacturing consumers a lot of forest products and water

Both forests and water are our valuable resources in Kenya and he should conserve as much of both.

Making use of waste paper and recycling paper can help us to achieve this.

Old newspapers can be used to make paper bags and for wrapping items.

Used office stationery and old newspapers can be collected shredded and mixed with water to make pulp.

Some of this paper pulp can also be made into thick paste called paper mache.

Paper mache can be used for modeling in the schools.

  1. candles

Candles are made of paraffin wax which melts very. When a candle has burnt out a lot of wax remain unused.

– All this unused wax can be scraped collected and melted to make new candles.

– One can also make some fancy type of multi – colored Christmas candles

– Used wax can also be used for modeling.

  1. Scrap metal

Whenever an object is prepared from raw metal some waste is left out in the form of granules or strips and is known as scrap metal.

The scrap of different metal is used for different functions:-

  • Iron dust is used to detect magnetic field and is obtained from wrought iron
  • Copper dust – may be widely used in chemical analysis of different substances
  • Copper turnings – are used in electroplating.

These turnings can be melted and drawn in the form of sheet or wire so as to be used again.

  • Zinc dust is melted and drawn into sheets so as to be reused. Zinc dust may also be used into the manufacture of batteries.
  • Iron scraps obtained from iron sheets can be used in the manufacture of batteries
  • A aluminum dirt obtained from aluminum sheets during manufacturing of useful products like utensils frames can be melted and used to make sheets.

Disposal of waste

  1. Polythene/Plastics

Plastic items should be labeled to enable people to know what type of plastic they are.

In some countries this because some plastics has poisonous dioxin

Plastics which are not made of materials which contain dioxin are disposed of by melting to make new items (re-cycled).

The soft ones made into baskets and the strong ones can be made into roofing tiles and posts.

  1. Sewage

The Sewage consists of human excretions and other waste released from houses toilets

Sewage can be used to produce biogas which can be as a fuel in households and to generate electricity for domestic use.

The residual matter, left in the digestive tank is good manure which farmers can use in their farms.

  1. Garbage


Garbage consists of organic materials like vegetables, grass, fruit, and peelings from the kitchen.

They are various ways of disposing garbage:-

  • Garbage can is used for making composite manure.
  • Some garbage like grass can be used as mulching
  • Some garbage such peels and beans pods may be given it animals as feeds.
  • In some advanced countries garbage from the kitchen is disposed of by grinds the garbage into powder from the sewage through pipes to the sewage plant.


  1. Having Herpes is a Terrible Experience and my Experience will help some hsv patients beware of Herbs from online doc. I was positive to the deadly virus called HERPES and I lost hope because I was outcast and rejected even by my closest friends. I searched on-line to know an enquirer about cure for HERPES and I read someone testimony on how he was cured from HSV-2 so I decided to contact the same herbalist called Dr kpudu because I know that nature has the power to heal everything. I contacted him to know how he can help me and he told me never to worry that he will help me with the natural herbs from God! After 2 days of contacting him, he told me that the cure has been ready and he sent it to me via UPS SPEED POST and it got to me after 4 days! I used the medicine as he instructed me (MORNING and EVENING) and I was cured! it’s really like a dream but i am so happy! That’s the reason I decided to also add more comments of Him so that more can be saved just like me! And if you need his help, you can email him on [email protected] or whatsapp +2348050406865.


Please enter your comment!
Please enter your name here