Primary Science Syllabus

Media Team @Educationnewshub.co.ke

SCIENCE

Introduction

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:

 

TOPICS

SESSION TOPIC DURATION
1.
  • PHILOSOPHY OF SCIENCE
  • METHODOLOGY
   8 HOURS
20 HOURS
2.

 

 
  • HEALTH EDUCATION
  • WEATHER AND ASTRONOMY
  • SOIL
  • ENVIRONMENT
   7 HOURS
  6 HOURS
  5 HOURS
  8 HOURS
3.
  • PLANTS
  • ANIMALS
  • FOOD AND NUTRITION
  • PROPERTIES OF MATTER
    7  HOURS
  7  HOURS
  8 HOURS
  8  HOURS
4.
  • SIMPLE MACHINES
  • WATER
  • ACIDS, BASES AND SALTS
   5 HOURS
  3 HOURS
  5 HOURS
5.
  • ENERGY
 14  HOURS
6.
  • HUMAN BODY
   9  HOURS
 

 

 

 

 

 

PHILOSOPHY OF SCIENCE

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;

1.3 Subtopics

1.4 What is science?

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

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

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

Teachers using this view to teach science will;

 

Advantages of static view

Disadvantages

1.42  Dynamic View

 

Teachers who use this view to teach science will:

Advantages of dynamic View

Disadvantages of dynamic View

 

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

Explain

 

Advantages of static view

 

Disadvantages of static view

 

1.6 SCIENTIFIC SKILLS

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.

Methods of recording include-:

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.

(iv)   Sorting and classifying

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.

(viii) Counting – involves allocating numbers to objects.

(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.

(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

variable.

– 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.

 

 

1.7   SCIENTIFIC ATTITUDES

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

The attitudes include:-

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

what would happen if?

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.

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

(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

Learners therefore need an open mind to learn science.

A pupil with an open mind:-

(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;

  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
  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.

Procedure

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

oscillations.

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

Design an experiment to answer this question.

 

 

 

 

 

2.0 METHODOLOGY

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

2.2.1 OBJECTIVES

2.2.2 APPROACHES TO TEACHING SCIENCES

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.
  1. Use questioning to develop the various cognitive levels {Bloomstaxonomy}

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
  1. Phrase question clearly
  2. Have sufficient wait time
  1. Address a question to the whole group and then identify the one answer
  2. Respond to learners’ response

2.2.4 METHODS OF TEACHING SCIENCE

2.2.5 RESOURCES FOR TEACHING SCIENCE

2.2.6 SCHEME OF WORK

2.2.7 LESSON PLAN

2.2.8 ASSESSMENT

 

SECTION 1: INTRODUCTION TO METHODOLOGY

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.

 

SECTION 2:  METHODS OF TEACHING SCIENCE

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.

 

 

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.

 

2.2.1 PATTERN OF CONDUCTING EXPERIMENT

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

 

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.

 

2.3 DEMONSTRATION

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:

 

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

The teacher should consider the following:

 

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.

 

 

 

 

2.4 DISCUSSION METHOD OF TEACHING/LEARNING

 

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

 

 

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.

 

Advantages of Discussion Method

 

 

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:

 

 

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

 

2.6 FIELD TRIP

 

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;

 

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.

 

Assignment:-

Find out and record the following

 

 

2.7 LECTURE

 

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:

 

 

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.

 

2.8 USE OF PROJECT

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.

 

Assignment:-

 

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

 

2.9 DRAMATIZATION/ROLE PLAY

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.

Assignment

 

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

 

SECTION 3 : RESOURCE FOR TEACHING SCIENCE

 

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.

 

3.1   LEARNING RESOURCES

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 e.tc 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

 

 

     3.2 TYPES OF LEARNING RESOURCES

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.

Advantages

Limitations

 

Specimens

Advantages

 

 

Disadvantages

Models

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

commercial, while others are made locally.

Advantages

Disadvantages 

 

Environment

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.

Visual Aids

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

photographs, charts, posters maps etc.

Posters

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

Charts

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

Pictures/Photographs

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.

Print

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

 

Experience Group

 

How to use a resource Persons

Preparation before the presentation:-

(i)  Discuss with resource person the following;

(ii)  Inform the learners about topic of discussion.

During presentation;

 

Improvisation

Advantages

 

Disadvantages of Improvisation

 

Activity

 

 

 

 

 

 

SECTION 4: SCHEME OF WORK

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.

 

4.1 PURPOSE OF A SCHEME OF WORK

Why it is necessary to prepare a scheme of work?

 

 

(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.

 

4.3.      COMPONENT OF A SCHEME OF WORK

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

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.

  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

(6)  EVALUATION

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.

IDENTIFYING INSTRUCTIONAL OBJECTIVES

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;

Thus a science lesson should have at least three objectives.

TYPES OF OBJECTIVES

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

STATING OBJECTIVES

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.

ILLUSTRATIVE VERBS FOR STATED INSTRUCTIONAL OBJECTIVES.

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

-Define

– Describe

-Label

-Match

– Name

– Outline

– State

COMPREHENSION                                             APPLICATION

– Solve

– Use

ANALYSIS                                                     SYNTHESIS    

EVALUATION 

Acceptable instructional objectives must fulfill the following qualities;

(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.

LEARNING ACTIVITY

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

Corresponding learning activities would be;

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

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

(7)  TEACHING / LEARNING RESOURCES

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

ty.

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

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

(8)  ASSESSMENT

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.

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

Assignment

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.

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

Assignment

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

 

SECTION 5:  LESSON PLAN

5.1 PURPOSE OF A LESSON PLAN

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)

LESSON PRESENTATION

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.

EXAMPLE

STEP 1

 

 TIME

 

 TEACHING ACTIVITIES LEARNING  ACTIVITIES

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

-motivate pupils
Development      
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.

 

 

CHALK BOARD PLAN

DATE SCIENCE PROPERTIES OF MATTER CLASS

STD 6
New words Soluble and insoluble solids

material apparatus

 

 

 

PROCEDURE

(1)

(2)

(3)

 

Observation

 

 

 Charts

Sketches

-Illustration

Self-Evaluation

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.

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.

 

2.2.8 ASSESSMENT

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.

FORMS OF ASSESSMENT

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.

 

Grade

-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

 

 

  1. Written tests

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

EXAMPLE

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

Example

            Animals                       Name of group

Cow                             Reptile

Frog                            Mammal

Lizard                         Amphibians

Bat                              Birds

Chameleon

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.

Example

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

Example

A chameleon is a reptile. True or False.

Setting multiple choice questions

  1. Write the stem first
  1. Write the key (correct response)

 

  1. Read the stem and the key

 

 

  1. Write the distracters

 

 

  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.

 

 

 

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.
  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.

BLOOM’S TAXONOMY

 

  COGNITIVE LEVEL
Topics

(Content)

 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.

 

LEVEL ABILITY REQUIRED COMMON VERBS USED
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

 -Describe

-Discuss

-Summarize

-Paraphrase

-Interpret

-Illustrate

-Predict
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 …

Compute…

Demonstrate…

Construct …

Show …

Modify…

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

 Analyze…

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 …

Design…

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…

Assess…

Recommend…

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

-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

  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

(diagram)

 

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

Application questions will involve the use of logic or reasoning

Examples

  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

ANALYSIS

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.

Examples

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

 

 

 

 

 

 

 

3.0 HEALTH EDUCATION

WORMS

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

Roundworm (Askaris)

Effect on Health

Prevention

Hookworms

How Hookworms Spread

Prevention

Tapeworms

How it Spreads

  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

Prevention

Common Communicable Diseases

Definition

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

Tuberculosis (T.B)

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

 

Frequent Signs

 

 

Serious/advanced Signs

 

 

In Children

 

 

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

 

 

To Check For Tuberculosis (T.B)

 

 

How To Manage Tuberclulosis (T.B)

 

 

Malaria

 

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

 

 

Signs

 

The attack has three stages

 

 

NB:-

 

 

Prevention

 

SKIN DISEASES

Skin problems are caused by

(a)  Scabies 

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

Most common:-

Causes of Scabies

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

How it spreads

Treatment

 

(b)  Ringworms (Tinea-Fungus Infection)

 

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

 

 

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.

 

 

Treatment

 

 

Prevention of fungus infections

 

All fungus infections ate contagious

 

WATERBORNE DISEASES

 

(a)  Cholera

 

 

Transmission

 

 

Prevention

 

 

(b)  Typhoid

 

 

Signs

 

1st Week

 

 

 

2nd Week

 

 

Treatment

 

Seek medical help.

 

Prevention

 

 

(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.

 

 

How Blood Flukes Spread

 

 

Signs

 

 

Prevention

 

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

 

 

(d)  Amoebiasis

 

Amoeba cannot be seen naked eyes.

 

Transmission

 

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.

 

Signs

 

Many healthy people have amoebas without getting sick.

 

 

Amoebic Dysentry Will Cause

 

out.

 

NB:-

 

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)

 

 

Treatment

 

Prevention

 

SEXUALLY TRANSMITTED INFECTIONS

 

Definition:

 

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

 

 

Signs in Men

 

 

After Weeks Or Months

 

 

Signs in Women

 

 

 

After Weeks Or Months

 

 

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.

 

Treatment

 

Seek medical help.

 

NB:-

 

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

 

 

 

 

Prevention

 

 

(b)  Syphilis

 

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

 

Signs

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

 

 

 

NB:-

 

 

Treatment

 

 

Prevention

 

Same as for gonorrhea.

 

(c)  Candidiasis

 

Otherwise known as thrush or moniliasis

 

Treatment

 

 

(d)  Herpes

 

Treatment

 

 

HIV AND AIDS

 

Definition

 

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.

 

(a)  MODES OF TRANSMISSION.

 

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:

 

 

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

 

 

(b)  Stages of Development

 

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

 

 

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?

 

 

Counseling

 

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.

 

NB:-

 

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

HIV.

  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:-

 

 

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

 

 

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

 

 

(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.

 

 

NB:-

 

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

 

 

  1. Hygiene

 

  1. Emotional Support

 

  1. First Aid and Home Nursing

 

  1. Developing Positive Attitudes

 

  1. Financial and Material Support

 

 

 

 

  1. Appropriate Information

 

IMMUNIZATION

 

Definition

 

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

 

Importance

 

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

Tetenus

Measles                                   9 months                                             Injection

 

NB:-

 

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.

3.9       Drugs

Definition:

 

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

 

 

Classification

 

Drugs may be classified into two categories.

 

(i)  Legal Drugs:-

 

 

(ii)  Illegal Drugs:-

 

 

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.

 

 

3.10     Drug and substance abuse

 

Definition

 

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:-

 

 

Effects of Smoking

 

ulcers.

own.

when they have not done it for a while.

 

NB:- 

 

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

 

  1. Alcohol

 

The effects of alcohol are immediate.

 

become drunk.

 

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
dementia.

 

  1. AMPHETAMINES

 

These are medications that doctors sometimes prescribe for depression.

 

snorted through the nose.

 

Effect

 

 

NB:-

 

 

  1. COCAINE (CRACK CAKE, SNOW WHITE LADY)

 

 

Effect

 

(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
disturbances.

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

 

NB:-

 

 

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

 

Effects 

 

 

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.

 

  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.

 

Effects

 

 

  1. HEROIN (‘Horse’, ‘smack’)

 

 

Effects

 

 

 

Other Risks From Heroin

 

(a)  Decreased immunological systems.

 

 

(b)  Chemical Adulterations

 

 

(c)  Hepatitis and AIDS

 

 

(d)  Hematomas

 

 

  1. INHALANTS

 

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

 

 

 

Effects

 

Other Risks Are:-

The speed of their effects

 

SOCIAL, HEALTH AND ECONOMIC IMPLICATIONS OF ABUSING DRUGS AND SUBSTANCES

 

Safety When Handling Chemicals Used At Home

 

4.0       TOPIC:  WEATHER AND ASTRONOMY

Introduction

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

Wind

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.

Rainfall

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.

Temparature

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.

Humidity

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)

Sunshine

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

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:

Activity

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

IMPROVISED WEATHER EQUIPMENTS

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

Wind

Various aspects of wind can be measured

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

CONTSTRUCTION OF IMPROVISED WEATHER INSTRUMENTS

Windvane

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.

Activity

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

 

Windsock

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.

 

Activity

Describe how a windsock can be used to measure

  1. The direction of wind
  2. Strength of wind

Raingauge

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.

Activity

  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.

Thermometer

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

Activity

  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

Activity

  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

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

HOW IT WORKS

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

Barometer

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.

RECORDING WEATHER

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.

SITE FOR A WEATHER STATION

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

RECORDING WEATHER

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

WEATHER CHART

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

 

WEATHER FORCASTING

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

Activity

Discuss the traditional beliefs about weather in your community

Discuss how the following factors affect weather

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

PROJECTS

This work should be done at home

Construct the following weather instruments

  1. Wind-vane
  2. Wind-sock
  1. Air thermometer
  2. Liquid thermometer
  3. Air barometer

ASTRONOMY

Definition:-

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

and comets.

 

Stars

A star is a huge ball of glowing gases.

the earth.

 

Constellations

(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)

 

 

 

 

(iii)  The Southern Cross

 

 

(iv) The scorpion

 

 

 

 

(v)  Canis major (great dog)

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

Galaxy

Large group of stars in outer space

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

 

Planets

There are eight planets in solar system.

 

Meteors

Small pieces of rock that circulate in space.

heat generated by friction with air.

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 of the Earth

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

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

 

 

 

 

Asteroid belt

 

Comets

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:-

 

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.

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

 

night is dark.

(getting smaller)

 

 

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

sun, moon and earth.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5.0 SOIL

DEFINATION

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.

Importance.

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.

E.g.

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

-wind

– 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

 

 

 

 

Field

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.

–

 

 

 

 

 

 

 

6.0 PLANTS

6.1 SPECIFIC OBJECTIVES

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.

 

 6.2.1 THE CHARACTERISTICS OF PLANTS

Plants show the following characteristics:-

  1. They respire.
  2. They reproduce.
  1. They excrete.
  2. They reproduce.
  3. They respond to stimuli (irritability).

 

     6.2.2   CLASSIFICATION OF PLANTS

Plants can be classified into

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

GREEN AND NON-GREEN PLANTS.

  1. GREEN 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.

EXAMPLES

 

NON-GREEN PLANTS

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

EXAMPLES

 FLOWERING AND NON-FLOWERING PLANTS

NON-FLOWERING PLANTS

EXAMPLE

.  Mosses

.  Liverworts

.  Fungi

.  Ferns

FLOWERING PLANTS

.  Dicotyledonous

.  Monocotyledonous

  1. DICOTYLEDONOUS

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

Eg Coffee, tea, hibiscus

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

                           MONOCOTYLEDONOUS

  1. C) STRUCTURE AND FUNCTIONS OF MAIN PARTS OF A PLANT

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

  1. Leaves
  2. stem

LEAVES

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

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
  1. STRUCTURE OF A STEM

.  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

There are two main root system

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

 

6.2.5 FLOWERS

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.

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

 

  1. FUNCTIONS

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

  1. POLLINATION

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.

ACTIVITY

1a)  State the agents of pollination.

  1. Describe characteristics of insect and wind pollinated flowers.

 

FERTILIZATION

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.

 

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

  1. C) STRUCTURE OF SEEDS

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

It consists of

6.2.6   SEEDS AND FRUIT DISPASAL

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

  1. Significance of seed and fruit dispersal

 

  1. Agents of seed and fruit dispersal.

Agents of dispersal includes includes.

  1. Wind
  2. Water
  1. Self dispersal mechanism

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

 

ACTIVITY

Explain how the following agents help in seed and fruit dispersal

  1. Wind
  2. Water
  1. Self dispersal

 

GERMINATION OF SEEDS

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

During germination

 

Conditions necessary for germination.

To germinate a seed requires water, oxygen and warmth

WATER

.  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.

 

OXYGEN

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

 

TEMPRETURE / WARMTH

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

ACTIVITY

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

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

 

TYPES 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.

6.2.7 VEGETATIVE REPRODUCTION IN PLANTS.

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
  1. Stem tubers
  2. Creeping stems e.g.- runners

-stolons

– Suckers

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

 

ACTIVITY

Draw and write a brief description of

ADVANTAGES OF VEGETATIVE REPRODUCTIVE IN PLANTS.

 

DISADVANTAGES OF VEGETATIVE REPRODUCTION IN PLANTS

 

6.2.8                                                                CROPS

Definition

Plants grown for economic purpose or consumption.

Types Food Crops

CASH CROPS

Grown for economic purpose (income) they are:-

Beverages

Fibre

Oil

Beverage make drinks – tea, coffee or cocoa.

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

Fibre

Priovide fibre e.g.

Cotton

Sisal

Coconut

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

 

Oil Crops

 

The plants provide oil e.g.

Sunflower

Castor

Coconut

 

CROPS PESTS

 

Divided in two categories

 

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.

Effects

 

 

Control

 

 

6.2.10                                                         CROP DISEASE

 

Deviation from good health.Signs of unhealthy crops.

 

 

Harmful effects

 

 

6.2.11                                                              WEEDS

 

Definition – a plant growing where it is not needed.

Types of Weeds

 

Assignment identification of various types of weeds

 

Advantage of weeds

 

 

Disadvantage

 

 

Control of Weeds

 

Cultural Method

 

 

Assignment on chemical use.

 

 

 

 

 

 

 

 

 

 

 

7.0. ANIMALS

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

Comparison of characteristics of animals and plants

  ANIMALS   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

INVERTEBRATES AND SUB-GROUPS

These are animals which do not have backbone (notochords)

Invertebrates can further be subdivided into the following phyla

i).       Protozoa

Characteristics

 

 

  1. ii) Porifera

Characteristics

 

iii)        Coelenterates

Characteristics

 

  1. iv) Echinoderms

Characteristics

  1. v) Molluses

            Characteristics

  1. vi) Annelids

Characteristics

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

vii)    Nematodes

 

    Characteristics

 

Examples

 

Roundworms

Hookworm

Threadworm

 

 

 

Platy helminthes (flatworms)

 

Characteristics

 

Examples

Planaria

Liver fluke

Tape worm

 

They can further be subdivided into the following classes

-Trematoda

-Monogenea

Cestoda

Turbellaric

Arthropoda

 

    Characteristics

 

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

 

Vertebrates

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

Characteristics

 

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

2.AMPHIBIAN

            Characteristics

-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

  1. REPTILIA

            Characteristics

-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

 

  1. PIECES (THE FISHES)

            Characteristics

-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

  1. MAMMALIA

            Characteristics

–           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

Cattle

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

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:-

 

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.

 

Effects

Control

 

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

 

Effects

 

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

-Hay

-silage

 

Characteristics

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

Eg

 

 

Characteristics

 

Methods of grazing                   

 

There are various methods of grazing cattle.

Example

 

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 :-

 

Advantages of rotational grazing

 

 

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

 

Advantages

 

Disadvantages

 

Herding

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

 

  1. 0 PROPERTIES OF MATTER

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

8.2.3 Properties of liquids and their applications

8.2.4 Properties of gases and their applications

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

 

KINETIC THEORY AND CHANGE OF STATE

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?

 

Discussion

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.

Heating

 
 
 

Melting                                 Vaporization

Freezing                               Condensation

Cooling

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

 

8.2.2 PROPERTIES OF SOLIDS AND THEIR APPLICATIONS

Hardness

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.

Brittleness

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

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.

Procedure

Measure the dimensions of the regular solid.  Weigh out the solid to determine its mass.

Calculations

V = axb x c cubic units

=  abc cubic units

Mass, M =  mg

 

Density  = Mass

Volume

=  m   g/cubic units

g            m       g/cm3

Abc

Abc

 

 

 

 

 

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

Volume

 

  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

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)
A      
B      
C      

 

Discussion

The pressure varies depending on the area of the face.  The smaller the area the larger the pressure.

 

Applications

  1. Sharp objects exert more pressure than blunt ones.
  2. Carrying a bag with wide belt reduces the pressure exerted on the shoulder.

 

Activity

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?

 

 

 

Discussion

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.

 

Discussion

 

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

 

 

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.

Solubility

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.

 

Procedure

  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
Sugar      
Salt      
Chalk powder      
Soil      

 

Discussion

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.

Suspension

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)

 

Applications

  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

 

8.2.3 PROPERTIES OF LIQUIDS

 

Boiling point

Exp.To determine the boiling point of water.

Method:  Water, container, source of heat, thermometer.

 

Procedure

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
Temperature              

 

Plot a graph of temperature against time.

 

Discussion

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.

 

PRESSURE

EXPERIMENT TO SHOW PRESSURE VARIATION IN LIQUIDS

Materials:  Container, pail, water, sell tape/masking tape.

Procedure:-

 

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.

 

Discussion

 

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
    pressure.

 

Shape

Put water in containers of different shapes.

 

 

 

 

 

 

The water takes the shape of the container.  Liquids have no definite shape.

Density

Exp. To determine density of water

Materials:  Container, measuring cylinder, water, weighing balance.

Procedure:-

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

Volume

MISCIBILITY

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.

 

EXPERIMENT TO INVESTIGATE MISCIBILITY IN LIQUIDS

Materials:  Water, Kerosene, methylated spirit, cooking oil, transparent containers stirrer

Procedure:-

(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    

 

Discussion;-

Miscible Liquids

  1. Water + Methylated Spririt
  2. Kerosene methylated spirit

Immiscible Liquids

  1. Cooking Oil + Water
  2. Kerosene + Water

 

 

 

Applications

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.

EXPANSION AND CONTRACTION

Experiment to demonstrate expansion of liquid

Materials:  Transparent container, water, capillary tube/straw (transparent), cork.

Procedure:

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.

Discussion

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

Application

  1. Principle of expansion of liquids is used in thermometers. Mercury and alcohol are used to
    show temperature changes.

8.2.3 PROPERTIES OF LIQUIDS

VISCOSITY

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.

Procedure:-

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.

Discussion

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.

Application

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.

Capillarity

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.

EXPERIMENT TO SHOW CAPILLARY ACTION

Materials:  Capillary tubes open ended at both sides, container, water and mercury.

Procedure

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.

Applications

  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.

EXPERIMENT TO DEMONSTRATE SURFACE TENSION

Materials:  Container, water, razor blade, soap solution.

Procedure

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.

Discussion

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.

Application

  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
    sink.

 

COHESIVE AND ADHESIVE FORCES

Activity 14

(ii)   Put mercury in a transparent container also and observe the shape of the meniscus.

(ii)   Repeat (b) (i) using mercury.

Discussion

(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.

Explanations

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.

Application

Cohesion reduce rate of evaporation.

8.2.4 PROPERTIES OF GASES

Pressure

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
observe.

Discussion

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.

 

Discussion

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.

Applications

  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
    liquid.

WEIGHT

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.

EXPANSION AND CONTRACTION OF AIR

Air expands on heating and contracts on cooling.

Activity 17

Arrange the apparatus as shown above .heat the glass flask gently and observe.

Discussion

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.

Application

  1. This heating and expanding of air can be used to explain formation of land breeze and sea
    breeze.

Exercise

Explain:

 

 

 

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;

 

 

 

USES OF AIR

Different components of air have different uses.

Activity 18 (In Groups)

Discuss the uses of

 

Activity 19

Design experiments to show that;

MIXTURES

When two or more substances are put together and not chemically combined.  There are three types of mixtures.

METHODS OF SEPARATION OF MIXTURES

Solid-Solid Mixtures

The following methods can be used to separate these mixtures.

Activity 20

Discuss each of the above methods.

Solid-Liquid Mixtures

The following methods can be used;

Activity 21

Discuss how each of the methods above are used.

Liquid-liquid mixtures

Activity 22

Discuss how each of the methods  mentioned above are used to separate liquid mixtures.

 

 

 

9.0 FOOD NUTRIENTS AND NUTRITIONAL DISORDERS

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

  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.

 

Protein

Functions of proteins in the body

Carbohydrates

Classification of carbohydrates

  1. Monosaccharide: glucose, fructose, galactose and mannose
  2. Disaccharides: sucrose, glycogen, cellulose (roughage)

 

Functions of carbohydrates in the body

Fats and oils

Functions of fats and oils

Vitamins

  1. water soluble vitamins all vitamin B (except B12) and vitamin C
  2. Fat- soluble vitamins. Include A,D,E,K

Minerals

Functions of minerals in the body

 

 

9.2.3 IMPORTANCE OF WATER IN THE DIET

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.

 

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

 

  1. Marasmus

Signs and symptoms

  1. Scurvy

Deficiency disease caused by lack of vitamin C in the diet

Symptoms of scurvy

  1. Iron- deficiency anaemia

Signs and symptoms

  1. Rickets

Signs and symptoms

  1. Osteomalcia

Signs and symptoms

  1. Beriberi

Signs and symptoms

Signs and symptoms of dry beriberi

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

  1. Pellagra

Caused by lack of nicotinic acid in the diet

Signs and symptoms

  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

  1. Keratomalacia

Signs and symptoms

 

9.2.6 Nutrition for special groups

Meals for  children

Meals for lactating mother  (breast feeding /nursing mother)

 

Points to consider:

9.2.7 FOOD HYGIENE

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

 

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

 

  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

NB:  all these produce toxins which poison the body.

 

Signs and symptoms of food poisoning

 

        Prevention of food poisoning and spoilage

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:

Advantages of Food Preservation

 

Disadvantages of Food Preservation

Methods of preserving food

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

Store in airtight containers

Drying root vegetables

Drying Cereals or pulses

Drying Meat fish

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

 

 

 

 

 

 

 

10.0 ENVIROMENT

10.1 Specific objectives

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

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.

Mutualism – This is an association which is beneficial to both and no harm is inflicted on either of the organisms.

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

Photosynthesis

    Commensalism 

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.

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.

Plants

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

hydrophytes

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

broken

(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.

 

Animals

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:-

This color combination makes it hard for the enemies to see the fish.

water.

10.2.7 Pollution

Sound pollution

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:-

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:-

10.2. 9 Handling waste

Making good use of waste materials

  1. Coffee husks
  1. Cow dung:-
  1. Ashes

Recycling of materials

Definition

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:-

These turnings can be melted and drawn in the form of sheet or wire so as to be used again.

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

Definition

Garbage consists of organic materials like vegetables, grass, fruit, and peelings from the kitchen.

They are various ways of disposing garbage:-

Related Articles
↑
Exit mobile version