INTRODUCTION

Science Elementary Technology is an essential subject with a significant application in our daily

life. This summary book is for primary four learners. Learners are then taken through examples,

study tips and Unit assessment. This book will help learners to study, practice, integrate and

assess him /herself

This SET Pamphlet is divided into 16 units and each unit has key competence, activities and

exercises.

NB: the summary we have are from unit.1 to unit 3 and unit 7 to unit 14 the rest we found

that are more practical than theoretical so it was very hard to set for them unities that need

some instructions and kinetic ways of teaching where they need personal computer to

imitate what teacher does to master the content.

1
Unit 1: Agricultural Tools
1.1 Identifying common Agricultural Tools

Activity-1: Identifying and naming some of Agricultural Tools Below;

1.2 Uses of Agricultural Tools

2
Fill the table below

Tool Use
Machete/ panga Is used for cutting and clearing shrubs and
bushes.
Hoe ...............................................................................
…………………………………….. Is used for transplanting seedlings.
Watering can …………………………………………………………….
…………………………………… Is used for sharpening cutting tools.
Wheelbarrow …………………………………………………………

Can you name some other agricultural tools?

1.3 Maintenance of Agricultural Tools

1. Tools must be cleaned properly after use.

2. After cleaning, tools must be stored in a safe, dry and termite-free place.
3. Digging and cutting tools should be kept sharp.
4. Plastic sprayers must be kept away from the fire. Pipes and nozzles must be
cleaned regularly to prevent blockages.
5. Damaged tools must be repaired properly.
6. Metallic tools like wheelbarrows must be painted regularly to avoid rusting.
7. On transporting tools and their parts, oiling and greasing have to be done
regularly.
8. Tools must be handled with care.
9. Tools must be used for the purpose they are designed for.
10. Records of the movement of tools must be kept.

1.4 Storage of Agricultural Tools

 Store all tools in a damp-proof or a dry room.

 Tools should be kept dry.
 Tools must be stored in fixed places.
 Damaged tools must be repaired and greased before storing.
 Tools we use often should be kept near the door.
 Storeroom should be locked to protect the tools from theft.

1.5 Dangers of the Misuse of Agricultural Tools

 You might injure yourself.

3
  You might injure your friends.
 You might damage the tools.
 You might inhale poison from agricultural chemical.

Unit Review Exercises

I. Fill in the blanks with the correct options:

1. Axes and machetes are .........................tools.

a) cutting b) watering

c) transporting d)clearing

2. .................................has toothed bars fixed diagonally to a handle.

a) Rake b) Spade

c) File d) Trowel

3. A trowel is a ............................tool.

a) Sharpening b) none of these

c) Cutting d) transplanting

4. A wheelbarrow is a ................... tool.

a) Transporting b) sharpening

c) Transplanting d) digging

5. ............... is a sharpening tool.

a) Machete b) Trowel

c) Spade d) File

II. Answer the following questions briefly:

1. What are agricultural tools?

2. List some common agricultural tools.

3. Write some methods of maintenance of agricultural tools.

4. Explain the dangers of the misuse of agricultural tools.

4
Unit 2: Objects Production
2.1 Making play objects or toys.

What are toys? Toys are things that we play with.

Examples of toys: rag dolls, paper footballs, toy cars, toy planes and others.

Toys can be made from clay, wires, reeds, sisal fibres, banana fibres, wood, sticks, manila
papers and others.

2.2 Making utility objects.

Utility objects are objects that we can use at home and at school.

Examples of utility objects: mats, trays, baskets and others.

Baskets can be made from things like: sticks, banana fibres, sisal fibres, grasses or reeds,
raffia, cane and others.

The art of making baskets is called basketry. Baskets can be made using methods such as:
weaving, twisting, intertwining, plaiting and coiling.

Baskets are used for:

a) Storing grains like maize and millet

b) Carrying items bought from a shop or market
c) Fishing

Dustbin or mat can be made from banana fibres and sisal fibres.

We put dirt and pieces of paper in dustbins.

We place hot dishes and plates on table mats.

We sit on mats.

Maintenance and storage of utility and learning objects

a) Store them in the science corner of your classroom.

b) Stick them on a large manila paper and hang them on the wall.
c) You can store the toys and dolls on racks or class cupboard or in boxes.
d) At home, store your toys in boxes or shelves

Unit Review Exercises

5
 Answer the following questions briefly:

1. What type of soil is used for making toys?

2. Name at least three objects made of clay.

3. List at least three objects made up of fibres.

Unit 3: Computer My Friend

 The computer is a basic need in every field.

Definition: A computer is one of ICT tools.

Other ICT tools include: mobile phones, calculators, radios, thermometers, and fax
machines.

These tools help us to use information and share it digitally.

(a) Computer

Fig. 1. An XO Laptop

A computer is a machine that accepts data and processes it. Finally, it produces
output (information) results.

Role of a Computer

A computer plays various roles in our daily life.

1. It can be used for personal computing.

2. It can be used for educational references.

6
 3. It can be used in the field of health and medicine.
4. It can be used for scientific research.
5. It can be used for communication and entertainment.

(b) Data and Information

 Data: Whatever you type from the keyboard is data. It may be

numbers, alphabets, and/or symbols.
 Information: Computer processes data. The processed data is
called information. In a computer, we can get information through
output devices, for example, monitor and printer.

(c) Communication

Communication is the process of sending or receiving information. We

can communicate by speaking, writing, through art and music, and books.

With a mobile phone, we can communicate with any part of the world. We can make
calls, send and receive text messages.

Role of Communication:

Communication plays an important role in our day-to-day life.

8. It is a source of information.
9. We know what is happening around the world.
10. Without communication, we cannot convey our thoughts and feelings.

(d) Technology

Technology is the collection of techniques, skills, methods, and processes used to

complete a work. Communication technology helps us to send and
receive information. With the help of communication technology, messages can be
sent within a moment around the globe.

7
Examples of technology used for communication are Internet, emails, fax, phones,
chat groups and social networking sites.

Internet, Website, and WWW

Internet: It is a large group of computers connected to each other. It is used to send

information quickly. It is widely used at hospitals, railway stations, airports, schools,
and offices.

Website: It is a collection of web pages. A website gives information about any

subject. Each website has its own web address. It can be reached through
an Internet connection by typing the domain name in the address bar. The
first opening page of a website is called homepage.

World Wide Web (WWW):

It is a collection of millions of electronic pages. These pages are interlinked just like a
spider’s web. These pages display a variety of information.

(e) Activity

Sugar is a collection of Activities. Activities are Applications that involve active

engagement from the learner. They automatically save results to a journal, where
reflections are recorded. Activities can be shared between learners.

(f) Projects

A project is a planned set of interrelated tasks. It should be completed over a

fixed period within certain cost and other limitations.

On websites, we get the necessary information regarding a project. Online

projects can be done with the help of related websites.

(g) Digital and Analogue Data

 Any signal or data which is expressed in digits (0–9) is called digital. For
example, digital watch displays the time by means of displayed digits.
 A system that represents changing values as continuously variable physical
quantities is called analogue.

(h) Hardware and Software

Computer Hardware refers to computer physical parts that can be touched.

For example, system unit, monitor, printer, keyboard, and mouse.

8
The software is a set of instructions for a computer to perform specific operations that
cannot be touched. For example, Windows Media Player for music and word processing.

3.2 Sugar Interface

Sugar interface is both a desktop and a collection of activities. Activities automatically save
results to a journal, where reflections are recorded.

You can write documents, share books and pictures or make music together with ease.

GNOME is a graphical user interface.

The GNOME desktop allows multiple workspaces to be active at any one time. We can move
from one application to another by clicking on one of the squares in the bottom toolbar.

Desktop computer.

The desktop has several special objects on it:

 The Computer icon gives you access to Compact Discs, removable media such
as pen drive, and also the entire file system.
 All of your personal files are kept in your Home Folder, labelled username’s
Home.
 You can also open this folder from the Places menu.
 The Trash is a special folder where you can place files and folders you no
longer need.

The Journal

In the sugar interface, all activities you do i.e. drawings, photographs, and writings
are automatically saved in the journal.
The journal is therefore used:
a) To help you remember what you did yesterday or the previous week.
b) To help you revisit old work
c) To help you resume incomplete work
9
 d) To help you organise your completed work.
e) To help you know how much you learnt with your XO laptop.
Journal Features

The Journal view contains a menu and a list of journal entries:

1. Star: You can mark important entries to help them stand out in the list by
clicking the star icon for that entry. When you click the star icon, the star is
coloured in.

2. Icon: Each Journal entry has an icon. The colour of the icon shows who
created the entry. For example, if you copy a photo from a friend, the photo’s
icon has your friend’s colours.

You can launch the Activity for the entry by clicking the icon. A hover menu may
reveal additional options. In particular, “Erase” deletes that entry from your Journal.

“Erase” deletes any data associated with the entry shown. For example, if
you delete an entry that shows that you installed an Activity, you delete the
Activity as well.

3. Entry name: Each entry has a name. You can edit the name by clicking it.

4. Buddy icons: If other participants join you in this Activity, icons in their colours will
appear here.

10
5. Elapsed time: The Journal displays the time since the most recent change to the
entry.

6. Detail view button: Click this button to see detailed information about the entry.
See “Journal detail view”, on next page.

7. Scroll bar: When there are more entries in the Journal than can fit on the screen,
you can use the scroll bar to scroll through them.

8. Search box: Type words in the box to search for entries that match those words.
Entries are displayed when they contain all of the typed words. Comparison will be
against all of:

o the entry name field

o the description field (see “Journal detail view”)
o the tag field (see “Journal detail view”)

9. Select by type (Anything): Choose an entry type to display only entries of that
type. Types include the Activity that created an entry, or the object type, such as,
picture, sound, text, and so on.

10. Filter by date (Anytime): You can limit the Journal View to entries made within
the past day, week, or month.

Journal Detail View

Components of Journal Detail view

The Detail view appears when you click the Detail view button for an entry. This
view lets you examine and annotate the entry. The detail view has the following
components.

1. Back icon line: You can click anywhere in this line to return to the main
Journal View.

2. Star and icon: These items duplicate their functions on the main Journal
view—a star represents a special, never-deleted Journal entry and the icon
colour indicates who created it originally.

3. Thumbnail image: Each entry has a thumbnail image that is created

automatically. The image shows the Activity screen when the last change to the
Journal entry was saved.

4. Entry name: You can change the name of the entry by clicking it and typing in
a new name.

5. Elapsed time: Displays the time since the most recent change to the entry.

11
 6. Description field: You can type a description of the entry in this field. Use a
description to remind you of what you did.

7. Tag field: You can enter search tags. Use keywords to describe a journal entry
so that you can find it later using the Search box in the main Journal view.

8. Participants: Displays the XO icons of each person who participated in a

shared Activity.

9. Resume button: You can click the Resume button to resume an Activity. A
hover menu may show additional options. For example, you can resume
working with an image using either the Browser or the Paint Activity.

10. Copy button: You can copy a Journal entry to the clipboard (or to one of the
removable storage devices shown on the bottom edge of the Journal screen) by
clicking the Copy button.

11. Erase button: You can erase an entry by clicking the Erase button.

Using Removable Media

1. Plug a flash dish into the XO laptop.

2. Push on magnifying glass key to open Journal.

3. Write on the notebook two icons found on the button of Journal.
4. Open the Universal Serial Bus (USB) device by clicking on the icon
representing flash disk on the bottom of the Journal.
5. Click on Journal icon besides the USB device icon to see the activities saved in
Journal.
The Journal also supports external storage media such as USB device or Secure
Digital (SD) card.

Use of removable media in Journal

Saving Entries from Journal to USB Device

1. Plug USB device into XO laptop.

2. Open Journal.

3. Point on the entry you want to move and hold the touchpad key.
4. Drag down to the USB device icon.
Saving Entries from USB Device to Journal

1. Plug USB device into XO laptop.

2. Open Journal.
3. Click on USB icon to view its content.

12
 4. Point on the entry you want to move and hold the touchpad key.
5. Drag down to the Journal icon.
To Remove USB Device

Hover over the icon of USB device and on the appeared menu, click Unmount or
Remove option.

Removing USB device

Sending Documents to Each Other

Find your friend’s XO Friend in the Neighbourhood view. In your friend’s pop-up
palette menu select Make friend.
Use the search text box in the Neighbourhood view tool bar to find a known XO
Friend name.

Review Exercises

I. Fill in the blanks with the correct options:

1. ....................... tools help us use information and share it digitally.

(a) ICT (b) UPS

(c) DATA (d) Website

2. .................... is a collection of web pages.

(a) Data (b) Website

(c) Digital (d) Analogue

3. The ................. lies behind all other components on your screen.

(a) mouse (b) keyboard

(c) desktop (d) none of these

4. The ............ is a special folder where you can place files and folders you no longer
need.

13
(a) window (b) home
(c) icon (d) trash

5. ............... is a type of computer program that allows you to perform a particular

task.

(a) Application (b) Text Editor

(c) Calculator (d) Character map

II. Answer the following questions briefly:

1. What are the roles of a computer?

2. Differentiate between data and information.

3 Write the steps to switch on and switch off a computer.

4. What is Journal Activity?

14
Unit 7: Air, Wind and Sound
 Air is what everybody breathes.
 It is a mixture of gases.
 Moving air is called wind.
 Air is the gaseous medium through which sound propagates.
 Air is everywhere. We cannot see it. We can only feel it.

7.1 Main Properties of Air

(a) Air occupies space

(b) Air has weight

(c) Air can be compressed

Composition of Air

Air is a mixture of various gases. It consists of the following gases:

-Nitrogen 78%,
-Oxygen 21% (one-fifth of air),
-Rare gases like Argon 0.97%, and
-Carbon dioxide 0.03%.

Utility of Air Components in Daily Life

Air has different components. Each component has some specific use. Some of them
are:

(a) Nitrogen

a) Nitrogen prevents rapid burning.

b) Nitrogen is used in the preparation of fertilisers.

(b) Oxygen

15
 a) Oxygen is used in respiration for both animals and plants.
b) It is used for combustion (supports burning).
c) Oxygen is necessary for plant germination.

(c) Argon (Rare gases)

 Argon is used in the lighting of bulb.

(d) Carbon Dioxide

 Carbon dioxide helps photosynthesis in green plants (photosynthesis is the

process by which green plants make their own food)
 Carbon dioxide is used in the making of industrial beverages (soft drinks e.g.
Soda)

 Carbon dioxide is used in the fire extinguisher to put the fire off.

(e) Water Vapour

 Water vapour forms clouds and then falls as rain on earth. So it is essential
for life processes on earth.

16
7.4 Dangers of Components of Air

(a) Carbon Dioxide and Water Vapour

The atmospheric air contains a little amount of carbon dioxide and water vapour.

These are the most powerful greenhouse gases.

Charcoal stoves, brick kilns, factories and motor vehicles release carbon dioxide into
the atmosphere. Bushfire also increases the amount of carbon dioxide in the
atmosphere. This gas traps the heat released by the earth. As a result,
the atmospheric temperature increases.

Water vapour is produced during boiling of water. These vapours are suspended in
the atmosphere as clouds. These clouds trap the heat released by the earth. As a
result, the atmospheric temperature increases.

The process of rising atmospheric temperature is called global warming.

(b) Carbon Monoxide

Carbon monoxide is a poisonous gas.

17
Breathing carbon monoxide can cause headache, vomiting, nausea and loss of
consciousness. It is invisible, tasteless and non-irritating. It is released from charcoal
stoves, brick kilns, factories and motor vehicles when fuel burns. It is also released
from bushfires.

People in rural areas use wood/charcoal stoves to cook their food. Charcoal stoves
are a source of carbon monoxide. So never cook food inside a closed room.

To prevent atmosphere from global warming:

1. Reduce fuel consumption.

2. Walk, use bicycle or take public transport.

3. Encourage people to plant trees to preserve the rainforests.

4. Use solar and wind energy.

5. Maintain your vehicle properly.

6. Turn off your vehicles at the traffic lights.

7. Buy energy-efficient appliances.

18
 Wind and its Types

Moving air disturbs the flame. This moving air is called wind. It blows from
a particular direction.

(a) Light Wind

 The soft and pleasant movement of air is called light wind.

 Light wind can be noticed by smoke rising vertically from a mosquito coil.

(b) Breeze Wind

Wind with soothing feeling on a warm day is called

breeze wind. It blows at a certain speed.

(b) Storm Wind (strong wind)

When wind blows very fast, it is called storm. A storm can uproot trees and blow
away temporary houses. It can also damage bird’s nests, sheds, and crops. We must
not go out of our homes during a storm.

7.7 Uses of Air and Wind

Air and wind help animals and human in many ways.

 Air helps birds to fly in the sky.

 Wind helps in winnowing.

This is a process of separating lighter husk particles from heavier grains like corn, millet
and sorghum.

 Moving air helps the clothes to dry.

19
  Moving air helps the clouds to move for rain distribution.
 Moving air helps the boat to sail on water.

The moving air rotates the wheel of the windmill to generate electricity.

7.8 Dangers of Wind

1. Observe the pictures above and state what is happening?

2. What do strong winds do to trees and electric poles?

3. How can strong wind damage houses and properties?

4. Why is it unsafe to fly an airplane on a stormy day?

5. Why is it unsafe to sail a boat on a stormy day?

The following are some dangers of wind:

1. Strong winds can uproot the plants and electric poles.

20
2. It can damage our houses and other properties.

3. It can damage our crops.

4. On a stormy day, an airplane can lose its control and may crash.

5. Strong wind can make a boat sink.

7.9 Prevention of Dangers of Wind

1. Trimming the branches of trees, allows the wind to pass through and lowers the
chance of trees tumbling over.

2. Ask fishermen not to go for fishing on a stormy day.

3. Check the roof for loose tiles. They can get displaced by strong wind and hurt
someone.

4. Never go on a stormy day. You can get hurt.

7.10 Sound

Definition: Sound is a form of energy we hear. It comes from all around us. It comes
from:

‹‹ people when they talk.

‹‹ radios when they play.

‹‹ airplanes when they fly.

Even breathing makes a low sound.

(a) Sound Production

Sound is produced by vibrating objects for example when a drum is hit.

(c) Nature of Sound

Sounds may be soft or loud, high or low, and pleasant or unpleasant.

Some other nature of sound are:

1. Sound is a form of energy, just like electricity and light.

2. It is always produced by a source.

3. Sound waves cannot be transmitted through vacuum.

21
 4. Speed of sound varies in all three media.

(c) Sound Propagation and Transmission

Sound propagation and transmission means the movement of sound.

(a) Solids

(b) Air

(c) Liquids

(d) Production of Echo: Reflection of Sound

An echo is a reflected sound. It is produced when sound hits a hard surface.

Uses of echo

1) Bats use echoes to look for food and detect obstacles in their way.
2) Echoes are used to measure the depth of water.
3) A stethoscope used by doctors in hospitals uses echoes of the heartbeat.
4) Soldiers use echo sounds called sonar in submarines and in planes.

(f) Sound and noise

Soft sounds are pleasant and good to hear.

Loud sounds and unexpected sounds are unpleasant (not good) to hear.

Unpleasant sound is known as noise.

Things that produce loud sound include:

i. Music from a radio.

ii. Machines as power saws.

22
 iii. Cars and planes.
iv. Ambulance and fire engine sirens
v. Doorbell shrills.
vi. Screams and gun fire
vii. Animal voices

Prolonged exposure to noise has various harmful effects.

1. Loud noise can damage our ears.

2. Loud noise can also cause tinnitus. Tinnitus is like a ringing or buzzing in the ears or head.

3. Noise leads to emotional and behavioural stress.

4. Noise increases chances of diseases like headache, blood pressure and heart failure.

5. Noise leads to noise pollution.

(g) Protection of Ears from Noise

1. Stay away from noisy places.

2. Turn the volume down and get used to listening to quieter sounds.

3. Wear earmuffs.

4. Protect the ears of children those who are too young to protect their own.

5. Make people aware about the hazards of noise.

Review Exercises

I. Fill in the blanks with the correct options:

1. The percentage of nitrogen present in air is ........................................

(a) 78% (b) 21%

(c) 0.17% (d) none of these

2. …………….. supports combustion.

(a) Oxygen (b) Argon

(c) Nitrogen (d) Water vapour

3. …………. is a greenhouse gas.

23
 (a) Oxygen (b) Carbon dioxide

(c) Argon (d) None of these

4. …………. is used in light bulbs.

(a) Oxygen (b) Argon

(c) Nitrogen (d) Water vapour

5. …………. is produced when something vibrates.

(a) Sound (b) Light

(c) Air (d) Oxygen

IV. Answer the following questions briefly:

1. List different properties of air.

2. Explain the composition of air.

3. List the main types of wind.

4. State some uses of air and wind.

5. Define echo.

6. How can we protect our ears from noise?

Unit 8: Soil
Definition: Soil is the topmost layer of the earth’s surface, loose material on the
surface of the earth.

There are three main kinds of soil:

1. Loam. Loam is chiefly a mixture of sand and clay. It can hold enough water and air
for plants. It feels smooth.

2. Clay. Clay is made up of very fine particles. It can hold a lot of water but very little
air. It feels sticky when wet and forms clumps when dry.

24
 3. Sand. Sandy soil is made up of very small rock particles. They are bigger than clay
particles. Sand is found in desert areas. Sand cannot hold much water but it can hold
much air. It feels gritty.

Composition of soil

1. Air
2. Clay, sand, stones and humus.
3. Moisture or water

Characteristics of soil

1. It should have adequate amount of humus.

2. It should have high water-holding capacity.
3. It should be well aerated.
4. It should be deep because deep soil enables plants to grow well.
5. It should be easy to dig.

Uses of soil

1) Is used for plant growth

2) Home for some animals
3) Used for construction purposes
4) Is used for making pots and ceramics
5) Is used for mining

Soil erosion

Soil erosion is the removal of top soil from one place to another by the agents of soil
erosion.

Soil erosion reduces the fertility of soil. Farmers do not get good crop

Agents of Soil Erosion

The agents of soil erosion are: wind, water, animals and human beings.

The main agent of soil erosion is water.

Causes of soil erosion

The main causes of soil erosion are:

 Over stocking and over grazing

 Deforestation
 Burning the bush

25
 Types of soil erosion

There are four common types of soil erosion they are:

1) Splash erosion
2) Sheet erosion
3) Rill erosion
4) Gulley erosion

Prevention of soil erosion

Some methods of preventing soil erosion are:

 Terracing
 Planting cover crops and trees
 Making gabions and porous dams
 Ploughing across slopes
 Mulching
 Keeping the right number of animals on the farm

Review Exercises

I. Fill in the blanks with the correct options:

1. The topmost layer of the earth’s surface is called .........................................

(a) rock (b) soil

(c) stone (d) none of these

2. ............................ is trapped in the spaces between the grains of soil.

(a) Water (b) Air

(c) Roots (d) All of these

3. ............................ soil is best for plant growth.

(a) Sandy (b) Loamy

(c) Clayey (d) None of these

4. ............................ cause soil erosion.

(a) Step farming (b) Afforestation

(c) Deforestation (d) Soil covering

26
 IV. Answer the following questions briefly:
1. What are the different types of soil?
2. What is the composition of soil?
3. Write three uses of soil.
4. Soil is home to many animals. Can you name any three animals?
5. Write any three characteristics of fertile soil.
6. Mention one agent of soil erosion.
7. List different types of soil erosion.

8. Define soil

Unit 9: Animals
 There are different types of animals in the world we live in. Many animals are quite
similar to each other. Others are quite different.

Classification of animals
There are two classes (groups) of animals. These are:
 vertebrates
 invertebrates

Vertebrates
These are animals with backbones. They are divided into five groups.
These groups are:

(1) Mammals
They have the following characteristics:
1. Mammals have hairs on their body.
2. They (females) give birth to their young ones.
3. They (mothers) feed milk to their young ones.
Example: Cow

Cow is the best example of a mammal. It possesses a backbone, hair and

mammary glands. It gives birth to its young ones.

27
 External Features of a Cow

The main external body parts of a cow are:

A. Head: It contains the eyes, ears, mouth, horns and muzzle. This allows it to pick up
sounds from more than one direction at a time.

B. Tail: Tail is the section at the rear end of an animal’s body. It helps swat away
biting insects that may carry diseases.

C. Anus: Anus is the opening through which the waste is removed.

D. Abdomen: It helps in digestion of food.

E. Legs: Legs are used for locomotion.

F. Udder: It is the mammary gland hanging near the back legs. There are four teats in
the cow’s udder.

Internal Features of a Cow

Internal features of a cow

A. Heart: It pumps blood throughout the body.

28
 B. Alimentary canal: It is a tube running from mouth to anus. It helps in digestion of
food.

C. Lungs: They help in breathing.

D. Liver: It produces bile. Bile helps in digestion of fats.

(2) Birds
They have the following characteristics:

1. They have a backbone.

2. They have streamlined body.

3. They have a beak, wings and feathers.

4. Their feet are covered with scale.

5. They lay eggs.

Hen

A hen is the best example of a bird. It possesses a backbone, beak, wing and feathers.

It lays eggs.

External Features of a Hen

The main external body parts of a hen are:

A. Beak: Beak helps a hen to protect it from enemies. It is also used as teeth.

B. Head: It bears eyes, ears, beak and wallet.

C. Feathers: Feathers keep a hen’s body warm.

D. Legs: Legs help the hen walk. It also scratches the soil with its legs.

E. Scales: Scales are hard plates that cover a chicken’s toe.

29
Internal Features of a Hen

Fig. Internal features of a hen

Alimentary canal is a long tube-like organ. It starts at the beak and ends with the vent or
cloaca in the abdominal region. It consists of food pipe, crop, liver, gall bladder and
intestines.

¨ The food pipe carries the food from the mouth to the crop.

¨ The crop is a small sac-like structure where the food is stored for some time.

¨ Liver secretes bile which digests the fats.

¨ The gall bladder stores the bile produced by the liver.

¨ The small intestine absorbs nutrients from the digested food.

¨ The large intestine absorbs water and the remaining undigested food.

(3) Fish

The following are some characteristics of fish:

1. Fishes live in water.

2. They have a backbone.

3. They have a streamlined body.

4. They have scales on their skin.

5. They breathe through gills.

Examples: Tilapia and tuna

30
Tilapia is the best example of a fish. It possesses backbone. It lives in water. It has scales on
its body. It breathes through gills.

External Features of Tilapia

The main external body parts of a Tilapia fish are:

A. Nostrils: A fish uses it to detect food.

B. Dorsal Fin: The fish uses it for balancing and protection.

C. Scales: Scales are the protective cover on a fish. It is similar to skin.

D. Caudal or Tail Fin: The fish uses it for steering.

E. Pelvic Fin: The fish uses it for steering.

F. Pectoral Fin: The fish uses it for turning.

Internal Features of Tilapia

The main internal body parts of a tilapia are gills. Fishes breathe through their gills.

Internal features of tilapia

(d) Reptiles

31
They have the following characteristics:

1. They have a backbone.

2. They move by crawling.

3. They have scales on their body.

4. They lay eggs on land.

Snake

Snake is the best example of a reptile. It possesses a backbone and scales on

its body. It moves by crawling. It also lays eggs.

External Features of a Snake

The main external body parts of a snake are:

A. Head: It contains eyes, nostrils, mouth and brain.

B. Scales: Scales protect them from wearing away. Scales also help them move.

C. Tail: It is the end part of the body.

32
Internal Features of a Snake

Water snakes also have gills.

Fig. 4. Internal features of a snake

A. Gills: These help the snake to breathe in water.

B. Liver: It secretes bile which helps in the digestion of fats.

C. Stomach: It is the main internal organ in which digestion of food occurs.

D. Small intestine: It is a long narrow coiled tube. It absorbs nutrient from the food.

F. Large intestine: It absorbs water from wastes.

Amphibians
They have the following characteristics:

1. Amphibians have a backbone.

2. They can live on both land and water.

3. They have a smooth slimy skin.

Frog is the best example of an amphibian. It possesses a backbone. It lives on both

land and in water. It has no scales on its body.

33
External Features of Frog

The main external body parts of a frog are:

A. Head: It contains the mouth, eyes, ears and nose. It protects internal organs like
brain.

B. Thorax: It is the part of the body between neck and abdomen. It protects internal
body parts such as lungs and the heart.

C. Abdomen: It protects the internal organs like stomach and intestines.

D. Legs: The legs help a frog to jump.

Internal Features of Frog

A. Heart: It pumps out blood throughout the body.

B. Stomach: Its main function is to break down and digest food.

C. Intestines: The small intestine absorbs nutrients from the food. The large intestine
absorbs water from wastes.

34
Examples of invertebrates are:

 Insects
 Archnids
 Molluscs

The following are some major characteristics of invertebrates:

1. They do not have a backbone.

2. They cannot make their own food.

3. Some of them have hard body covering.

4. They make their young ones.

Some organisms like earthworms and insects like grasshoppers, houseflies and
butterflies are invertebrates.

Insects

1. How many legs do these animals have?

2. How do they feed?

3. What are these animals called?

These animals are called insects. Some examples of insects are locust,
butterfly, housefly, spider and bee.

35
The following are some characteristics of insects:

1. Insects have six legs.

2. Each insect has a pair of antennae or feelers.

3. Insects like butterfly have a proboscis to suck nectar from flowers.

4. Body of an insect is made up of head, thorax and abdomen.

5. Most insects have wings and can fly.

6. Insects breathe through their spiracles (or air holes).

Some major characteristics of vertebrates:

1. Vertebrates have a backbone.

2. They have an internal skeleton which protects their internal organs.

3. They have two pairs of limbs or fins for movement.

4. They have lungs or gills for breathing.

5. They have closed circulatory system

Review Exercises

I. Fill in the blanks with the correct options:

1. Animals having backbones are called ............ .

(a) vertebrates (b) invertebrates

36
(c) both (d) none of these

2. Animals lacking backbones are called ............ .

(a) vertebrates (b) invertebrates

(c) both (d) none of these

3. .................. is a mammal.

(a) Frog (b) Dog

(c) Snake (d) Fish

4. .................. is an amphibian.

(a) Snake (b) Lizard

(c) Newt (d) Crocodile

5. ............... is an egg-laying animal.

(a) Bat (b) Hen

(c) Whale (d) Cat

II. Answer the following questions briefly:

1. Define vertebrates.

2. List all five major classes of vertebrates.

3. Name two reptiles that lay eggs on land.

4. What do fish use for breathing?

5 Define invertebrates.

37
Unit 10: Animals Management
Rabbits are small mammals. They are used for meat, fur and as pets. Rabbits can be
found in woods, forests and grasslands. They live in the underground burrows. Pet
rabbits live in the hutches.

Conditions of a Good Rabbit Hutch

A good rabbit hutch should provide enough exercise space for the rabbit. It should
protect the rabbit from the predators.

1. Hutches should be airy.

2. Rabbits should have enough material to play with. For example, small toys, pipes
and ramps.

3. Hutches should be dry.

4. Hutches should be clean.

5. Litter areas should be lined with hay.

6. The space required for an adult rabbit is about 0.18 sq.m.

Differences Between Male and Female rabbits

1.The size of a female rabbit is comparatively large than a male rabbit of the same
age in the same breed.

2.The round face in females is unlike the block-like face in males.

3.Old females have dewlaps but males haven’t.

4.Males are more defensive than females.

5.Males produce more urine than females during the mating period.

38
Common diseases in rabbits

Disease Cause Prevention

Coccidiosis Protozoa Do not feed rabbits with
contaminated feeds and
water
Ear scabies Mites Maintaining high
standards of cleanliness in
the hutch

Disinfect the hatch

regularly
Pneumonia Bacteria that attack the Avoid overcrowding
respiratory system
Isolate and kill all the
infected rabbits to
prevent spread
Tape worm Parasites that live in the Maintain high standards
body of cleanliness in the hutch

Review Exercises

I. Fill in the blanks with the correct options:

1. A good rabbit hutch should be ………………….. .

(a) stuffy (b) airy

(c) oppressive (d) none of these

2. The space required for an adult rabbit is …………………… .

(a) 1.18 sq.m (b) 0.18 sq.m

(c) 0.17 sq.m (d) all of these

3. A female rabbit is …………………………. than a male rabbit of the same breed.

(a) smaller (b) larger

(c) lighter (d) none of these

IV. Answer the following questions briefly:

1. List two conditions of a good rabbit hutch.

2. Distinguish a male rabbit from a female rabbit.

39
 3. What does a rabbit feed on?

Unit 11: Plants

Plants are found everywhere in our environment. Some of these plants are
planted while others grow on their own.

Germination: Is the process in which a seed starts to develop into a seedling

(young plant)

Conditions Necessary for Seed Germination

Oxygen, water and suitable temperature are the necessary conditions for viable seeds to
germinate.

Types of Germination

Epigeal germination Hypogeal germination

Stages of Germination

The process of germination occurs in the following four stages:

40
‹‹Stage 1: The seed takes in water and becomes swollen. The seed coat splits.

‹‹Stage 2: Baby root begins to grow. It grows downwards.

‹‹Stage 3: Baby shoot begins to grow.

‹‹Stage 4: The first leaves grow. The seed leaves shrivel. The food has been used up
by the baby plant.

11.5 Types of Plants

(A) Trees

Some plants are very tall. They have hard, strong, and thick stems called trunk.

These plants are called trees. Trees live many years. Examples: mango tree, acacia
tree, eucalyptus tree and avocado tree.

(B) Shrubs

Some plants are smaller than trees. They have hard stems with many branches.

Such plants are called shrubs. They live for a few years. Examples: Hibiscus, cotton,
rose and tea plant.

(C) Herbs

Some plants are very small. They have thin, soft stems. They live for one season or
for a few months. Such plants are called herbs. Examples: grass, mint, spinach,
coriander and garden eggplant.

Parts of a Plant and their Functions

41
A flowering plant has many parts. These are roots, stems, leaves, flowers and fruits.

Different parts of a plant

A flowering plant has many parts. These are roots, stems, leaves, flowers and fruits.

Functions of Parts of the Plant

(a) Root

It is the underground part of the plant. It has the following functions:

1. Roots fix the plant into the soil.

2. They absorb water and minerals from the soil. Water and minerals are important
for plants to grow healthy.

3. In some plants, roots store extra food. For example, carrot, radish and beetroot.

(b) Stem

It is the aerial part of a plant. It has the following functions:

1. The stem supports branches which bear leaves, buds, flowers and fruits.

2. It transports water and minerals from the roots to the leaves and fruits.

3. In some plants, stems store extra food. We eat these stems. For example, Irish
potato, ginger and sugarcane.

42
(c) Leaf

It is the most important part of a plant. Most plants have green leaves. Some
functions of a green leaf are:

1. A green leaf makes food for the plant.

2. Air and water vapour go in and out of the leaf. Thus it helps the plant to breathe.

3. In some plants, leaves store extra food. We eat these leaves. For example,
spinach, cabbage and coriander.

(d) Flower

Flowers are colourful and pretty. They are the reproductive parts of a plant. Some
functions of the flower are:

1. Flowers turn into fruits.

2. They give off a sweet smell. So they are used to decorate houses and gardens.

3. Flowers like pyrethrum are natural insecticides.

4. We eat some flowers, for example, cauliflower and broccoli.

43
 (e) Fruits

Fruits are produced from the flowers. Fruits like mango and coconut are one seeded.
Other fruits like pawpaw and guava are many seeded. Some functions of fruits are:

1. Fruits protect the seeds.

2. Fruits are a part of our diet.

3. Fruits are rich in minerals and vitamins.

They keeps us healthy.

4. Fruits bear seeds which help in reproduction.

5. Seeds of some fruits like black pepper are used as medicines and spices.

Unit Review Exercises

I. Fill in the blanks with the correct options:

1. When a seed gets enough air, water and sunlight, it grows into a seedling.

This process is known as .........................................................................

(a) germination (b) pollination

(c) dispersion (d) none of these

2. The tall plants are called ……………… .

(a) shrubs (b) herbs

(c) trees (d) none of these

3. ………….. live for one season or for a few months.

(a) Shrubs (b) Trees

44
(c) Herbs (d) All of these

4. Fruits are produced from ……………… .

(a) roots (b) stems

(c) leaves (d) flowers

5. …………. transports water and minerals from the roots to the leaves and fruits.

(a) Root (b) Leaf

(c) Stem (d) Flower

IV. Answer the following questions briefly:

1. Define germination.
2. List two types of germination.
3. Define trunk of a tree.

Unit 12: Human Sensory Organs

12.1 Functional Mechanism of All Sensory Organs

Sensory organs are connected to the brain through nerves. They work as follows:

 Each sensory organ receives stimuli such as touch, heat, cold and pressure
from the environment.
 The sensory organ transmits this information to the brain through sensory
nerves.

45
  The brain interprets this information and gives feedback to the sensory organ
through motor nerves.

Structure, Function and Maintenance of Sensory Organs

(a) Skin

Skin is the outermost covering of our body.

It is the sensory organ for touch and feel.

Parts/Layers of Human Skin

A. Dermis
B. Epidermis
C. Endodermis/hypodermis

Function of Skin

1. Run around your school playground twice.

2. Now observe your skin.

What is formed on your body?

The substance you see on your body is sweat. Others can say you are sweating.

The main functions of the skin include:

1. It allows us to have a sense of touch.

2. It protects our body from harmful germs.

3. It regulates our body temperature.

4. It helps us to release waste products as sweat.

46
 Some common skin diseases

Skin Disease Cause

Eczema  Early introduction of cow’s milk or
eggs to infants
 Contact with allergy causing
substances.

Ringworms  Caused by fungi

 Scaly patches form on the skin

Scabies  Caused by mites

Chicken pox  Caused by a virus

 Is common in unhygienic
conditions

(A) Wounds

Wounds are injuries that break the skin. They include cuts, scrapes and scratches.

First aid for the wound:

1. Clean the wound with a cotton soaked with antiseptic lotion. It removes dirt.

2. Put another ball of cotton soaked with antiseptic lotion. Tie a bandage around it. It
will help to stop the blood flow.

(B) Bruises

A bruise is a black or blue mark on the skin. It is caused by blood trapped under the
skin. Bruises are often painful and swollen.

First aid for the bruises:

1. Put an ice pack over the bruise. You can put a cloth soaked with cold water on the
affected area.

2. Rest the affected area.

(C) Burns and Scalds

47
 A burn is a damage to your body’s skin caused by heat. Heat from chemicals, hot
metal and burning are the most common causes of burns.

Scald is a skin injury caused by wet heat. Hot liquids cause scalds.

Both burns and scalds can cause swelling, blistering and scarring.

First aid for the burns and scalds:

1. Wash the affected area with cold running water.

2. Put an ice pack over the affected area for about 5 to 10 minutes.

3. Apply an antiseptic cream over the affected area.

Parts of Tongue

The surface of the tongue has small buds called taste buds.

They are present in different areas of the tongue. These buds help us to taste salt,
sugar and lemon.

12.3 Functions of the tongue

1. It enables us to detect various tastes.

2. It helps in chewing food and rolls it into food pipe.

3. It helps to clean food particles stuck between gums and teeth.

48
 12.4 Hygiene of the tongue

A clean tongue cannot be attacked by diseases. So it is important to keep our tongue clean.

To keep your tongue clean:

1. Wash your mouth before and after taking food.

2. Clean your tongue with a soft tongue cleaner.

3. Clean your tongue twice daily—in the morning and at night.

Proper Method of Cleaning Tongue

1. Choose a cleaning tool (e.g., a tongue cleaner).

2. Scrap the tongue first.

3. Rinse the mouth with clean water.

12.5 Tongue Disorders or Problems

The following are some tongue disorders:

(A) Sore: In case of sore, there are white or red patches seen on the tongue.

Sores are often painful. A person with sore on the tongue finds eating spicy foods
difficult. Sores may be caused by viruses. If you have sore:

(a) Avoid hot and spicy foods.

(b) Take soft foods and cold beverages until the sore heals.

(B) Swelling of tongue: Sometimes tongue may suddenly swell up in size.

49
 It is a symptom of disease like tongue cancer. If you have such a problem,
immediately consult a doctor.

(C) Black hairy tongue: In this case, the tongue appears to be hairy. It is caused by a course
of antibiotics.

If you have black hairy tongue:

(a) Scrap your tongue with a special tongue scrapper regularly.

(b) Avoid smoking.

(D) Loss of sense of taste: Sometimes people lose the ability to taste sour, salty,
bitter, or sweet flavours partially or completely.

Poor oral hygiene and dental problems are the causes of this.

If you have a taste disorder, consult a doctor.

(c) Nose

The nose is the sensory organ for smell.

Smells flow in air. Our nose picks up the air when we breathe in. Brain instantly tells
whether the smell is good or bad. In the above activity, it was the nose which helped
to smell the perfume.

The following are some common nose diseases:

(A) Common Cold

The common cold is a viral infectious disease. A person with common cold feels
a runny nose. He/She sneezes from time to time. It causes headache and weakness.

Causes of Common Cold

The causes of common cold include:

1. Transmission of cold viruses through air-borne droplets

2. Cold weather condition such as rain or winter

3. Poor immune functions

4. Insufficient sleep and malnutrition.

(B) Sinusitis

50
 It is an infection of the sinuses near the nose. When a person suffers from
sinusitis, his/her nose is blocked. He/She does not breathe well. He/She has
headache and facial discomfort.

Causes of Sinusitis

The causes of sinusitis include:

1. Microorganisms such as virus, bacterium or fungus

2. Abnormalities in the structure of the nose

3. It can be caused by allergy and irritation of sinuses.

Prevention of Nose Diseases

The following measures should be taken to prevent nose diseases:

1. Avoid close contact with the people who are sick.

2. Wear face mask when you are in crowds.

3. Cover your mouth and nose while others are sneezing or coughing.

4. Wash your hands with a soap. It reduces the spread of viruses.

(d) Ear

Ears are our sensory organs of hearing. We have a pair of ears on either side of
our head.

We hear sounds with our ears. When our ears are covered, we will not be able to
hear sounds.

Parts of Ear

There are three major parts of an ear. These are the outer ear, the middle
ear and the inner ear.

1. The outer ear: It is the part of the ear which can be seen. It helps us to receive
sound waves from the environment. Then it sends them towards the other parts of
the ears. It has the following parts

 The pinna: It is made up of a cartilage and skin. This is the entrance for the
sound waves

51
  The ear canal: It is a canal that guides the sound towards the inner ear. The
glands which release ear wax are positioned in the ear canal.

2. The middle ear: It is located in between outer and inner ears. It is a cavity filled
with air. It converts sound waves into pressure waves with the help of these parts:

 Eardrum: It is a delicate membrane. It separates the outer ear from the

middle ear. When sound reaches it, it turns into mechanical energy.
 Hammer: It is one of the three bones located next to the eardrum. It vibrates
when sound reaches it.
 Anvil: It is another tiny bone which vibrates in response to the previous
vibration.
 Stirrup: It is the last bone of the ear. It receives the vibration from the other
two bones and sends it into the inner ear.

3. The inner ear: It is the last part of the ear. It is filled with a watery substance. It is
made up of three parts which help in hearing.

 Cochlea: It is a spiral shaped tube. It is covered with small hairs which contain
nervous cells. Sound messages are picked from cochlea and sent to the brain.
 Semi-circular canals: They are connected with the cochlea and are filled with
fluid. They maintain the body balance and posture.
 The auditory nerve: It picks up sound messages from cochlea and sends them
to the brain.

Functions of Ears

The following are some specific functions of the ears:

1. They help in hearing sound.

2. They help in balancing our body.

52
 Hygiene of Ears

Regular cleaning of ears prevents some ear problems. Therefore, these should be cleaned
properly.

1. Do not clean your ears with toothpicks, matchsticks or any sharp objects.

It can injure the delicate part of the ears.

2. Use cotton buds to clean your ears.

3. Keep you away from loud sound. Loud sound can damage the ears.

4. Do not push things like beads and small stones into your ears.

Diseases of Ears and their Causes

Hearing Loss

Hearing loss is the reduced ability to hear sound. It occurs when sound waves do not
reach the brain. Basically, there are two types of hearing loss.

Some other causes of conductive hearing loss are:

1. Infection in the ear canal.

2. Tumour in the ear canal.

3. Much ear wax in the ear canal.

This disease is temporary. It can be cured by removing ear wax and other foreign
materials from the ears.

Some other causes of sensory hearing loss are:

1. Old age

2. Injury to the ear canal

3. Ear infection.

This disease can be cured by:

1. Treatment of ear infection

2. Avoiding travel in the vehicles which produce loud sound

3. Treatment of infection in the ear canal.

53
 Deafness

Deafness is the complete inability to hear sound. It is caused by damage to the inner
ear. Basically, there are three types of hearing loss. These are:

Partial Deafness

It is the condition in which a person is unable to hear properly.

It can be caused by the following factors:

1. Intrusion of foreign materials in the ear

2. Much ear wax in the ear canal

3. Holes in the ear drum.

This disease is temporary. It can be cured by removing ear wax and other foreign
materials from the ears.

Permanent Deafness

It is the condition in which a person is completely unable to hear. In some cases,

deafness is inherited from parents to their child. This type of deafness is permanent
and cannot be cured.

Sensory Deafness

It is due to the problem in the nervous system. A person with such a disease cannot
understand what he/she is hearing.

It can be caused by the following factors:

1. Disease of the blood vessels

2. Loud noises or sounds

3. Tumour in the ear canal

4. Use of certain medicines (drugs) that are harmful to hearing.

(e) Eye

The eyes are organs of sight. We have a pair of eyes.

The eyes are located in the bony cavities of the skull They are protected by the and
eye lashes.

54
Layers of an Eye

An eye is composed of three concentric layers:

1. Outer layer: This layer contains the sclera and the cornea.

 Sclera: This is the white part of an eye. It protects the eye from injury.
 Cornea: It is a curved, transparent circular coat in front of the eyeball.

It controls and focuses the entry of light into the eye.

2. Middle layer (Vascular layer): This layer contains the iris, ciliary body and choroid.

 Iris: It is a coloured, thin circular ball present in the centre of the eye. It
determines eye colour.
 Ciliary body: It is a structure that releases a transparent liquid in the eye. It
controls the shape of the lens. Lens is a solid body lying just behind the iris. It
provides focus of light on the retina.
 Choroid: It is a vascular layer of the eye. It lies between retina and the sclera.
It nourishes the outer layer of the retina.

3. Inner layer: This layer is also called retina. It is the sensory part of an eye.

 Retina: It is a very delicate coat at the back of the eyes. Images are formed on
the retina. The retina sends the images to the brain through nerves
called optic nerves.

55
 Chambers of an Eye

There are three chambers in the eye. They are:

1. Anterior chamber: It is the space between cornea, iris and the lens. It is filled with
a fluid called aqueous humour.

2. Posterior chamber: It is the space between iris and ciliary body. It is also filled
with aqueous humour.

3. Vitreous chamber (or Internal chamber): It is the space behind lens and between
iris and retina. It is filled with a clear jelly-like substance called vitreous humour.

Defects of Eyes and their Correction

Activity -27 Identifying the Types of Eye Defects

1. Search information from various sources (parents, peers, nearest health facilities,
printed materials and XO laptops about eye defects and their prevention.

2. Then share the information with your classmates.

There are many types of eye defects. These are:

(A) The girl is suffering from short-sightedness or myopia. She can see nearby
objects very well, but cannot see objects well that are far.

The following are some causes of short-sightedness:

1. Increased size of the eyeball

2. Weakness of eye muscles

3. Insufficient supply of blood to the eyes.

56
Correction

This defect can be corrected by using a convex (converging) lens.

(C) Presbyopia

Presbyopia is a progressive form of long-sightedness. It affects most people by their

early 60s.Most people find that the near point gradually diminishes.

Cause and Cure

It arises due to the gradual weakening of the eye muscles. Simple reading
eyeglasses with convex lenses correct most cases of presbyopia. Sometimes, a
person may suffer from both myopia and hypermetropia. Such people often require
bi-focal lenses. In the bi-focal lens, the upper portion of the bi-focal lens is a concave
lens, used for distant vision. The lower part of the bi-focal lens is a convex lens, used
for reading purposes.

(D) Astigmatism

In astigmatism, a person cannot simultaneously focus on both horizontal and vertical

objects.

Causes

57
 This defect is usually due to the cornea that is not perfectly spherical.

Correction

This defect can be corrected using eyeglasses with cylindrical lenses.

To prevent eye defects, respect the following advice:

1. Eat a healthy diet that includes fruit and green leafy vegetables.

2. Avoid smoking.

3. When you are outdoors, wear sunglasses that block sun’s harmful UV rays.

4. Keep at least a distance of 25 cm when you are reading and watching TV.

5. Have a regular checkup of your eyes by an eye doctor.

Unit Review Exercises

I. Fill in the blanks with the correct options:

1. Organs which help us to see, hear, smell, taste and feel are called ............. .

(a) breathing organs (b) sensory organs

(c) reproductive organs (d) none of these

2. ………… is the sensory organ for touch and feel.

(a) Ear (b) Eye

(c) Skin (d) Nose

3. ………… is the sensory organ of sight.

58
(a) Ear (b) Eye

(c) Skin (d) Nose

4. ………… is the sensory organ of taste.

(a) Ear (b) Eye

(c) Skin (d) Tongue

5. ………… is the sensory organ of hearing.

(a) Ear (b) Eye

(c) Skin (d) Nose

6. ………… is the sensory organ for smell.

(a) Ear (b) Eye

(c) Skin (d) Nose

II. Answer the following questions briefly:

1. Name any three skin diseases.

2. How can you take care of your tongue?

3. What are the specific functions of nose?

4. Mention some ear diseases and their causes.

5. How can you prevent eye defects?

59
Unit 13: Human Skeleton
 Skeleton supports our body. It is made up of bones. Without skeleton, we would not
be able to stand up.

13.1 Main Parts and Major Bones of the Skeleton

Skeleton gives shape and support to our body. A skeleton comprises skull, arms and
legs. Each of the major parts consists of some small bones.

Bones of the legs

The legs are called the hind-limbs. Each leg has three long bones and several short
bones. These bones make up the foot. Major bones of the leg are femur, tibia and

60
fibula.

The arms are called fore-limbs. Each arm has three long bones and several short
bones. These bones form the fingers and the hands. Major bones of an arm are
humerus, ulna and radius.
The upper part of an arm has a long bone. It is called humerus.
The lower part of an arm is made up of two bones—radius and ulna

13.2 Functions of the Skeletal System

Without skeletal system we would be just a puddle of skin. The skeleton gives shape
and support to our body. It has some other functions also. They are:
1. Together with muscles it helps us to move.
2. It protects all the delicate organs like brain and heart.
3. Some bones produce blood cells in the bone marrow. Marrow is a soft
tissue present inside the bone.
4. Bone tissues store minerals like calcium and phosphorus.
5. Bone regulates the release of hormones.
6. The facial bones form jaws which help us in speaking and eating.
7. The vertebral column or spine protects the spinal cord.

13.3 Accidents of Bones

When damages occur to the bones, it is called bone accidents. Fracture is one type
of accident to the bone.

The person is suffering from fracture. A break or crack in the bone is called a
fracture. Fractures can occur to the bones of legs, arms, head and backbones. A
sudden fall or an accident can cause fracture.
The following are the signs and symptoms of fractures:
1. Swelling or bruising over a bone.
2. The injured limb appears shorter.
3. Pain in the injured area.
4. Loss of function in the injured area.

(a) Types of Fractures

61
There are two types of fractures. These are—open fracture and closed fracture.
1. Open fracture: When a fracture punctures the skin, it is called an open
fracture.
2. Closed fracture: When a fracture does not puncture the skin, it is called closed fracture.

(b) First Aid for Fracture

In case of fracture:
1. Do not move the fractured part.
2. Apply a splint (rigid material) to the injury. Tie a cardboard with a piece
of cloth around the fractured part.

Note: Do not secure the splint too tight. The circulation of blood will be stopped.

3. In case of hand fracture, use a sling to restrict the movement of the hand.
A sling is a triangular piece of cloth.

4. Rush the victim to a nearby health centre.

(c) Prevention of Accidents of Bones

To prevent bone accidents:
1. Never play dangerous games.
2. Never fight with your friends.
3. Take a well-balanced diet to keep your bones healthy. Especially, eat food rich in calcium.
4. Exercise regularly. It will make your bones strong.

13.4 Bone Diseases

Diseases that affect our bones are called bone diseases. There are many kinds of bone
diseases. Some of the common bone diseases are:

Disease Cause Symptom

Rickets Deficiency of  Painful joints
Calcium and vitamin  Bending of bones and
D backbone
 Swelling of wrists, ankles
and knees

62
Bone cancer Abnormal growth  Painful bones and joints
 Joint swelling and stiffness
 Fever
 Tiredness

Hygiene of the Skeleton

1. Eat diet rich in calcium and Vitamin D. For example, egg, fish, milk
and liver.
2. Do physical exercise. Like muscles, bones become stronger with exercise.
3. Drink plenty of water to maintain joint health.
4. Prevent falls as it can cause bones to break

Review Exercises
I. Fill in the blanks with the correct options:
1. Our body is supported by a framework of bones called ............... .
(a) Skeleton (b) tissue
(c) muscle (d) none of these
2. ………… encloses the brain.
(a) Pelvis (b) Skull
(c) Rib (d) None of these
4. A break or crack in the bone is called ………….
(a) Disease (b) fracture
(c) deformity (d) none of these
5. When the fracture punctures the skin, it is called ………….
(a) Open fracture (b) closed fracture
(c) deformity (d) none of these
6. ………… is the bone disease caused due to lack of Vitamin D.
(a) Scoliosis (b) Bone cancers
(c) Rickets (d) None of these

IV. Answer the following questions briefly:

1. what is a skeleton?
2. Which part of the skeleton protects the brain?
3. List major bones of the trunk.
5. List major bones of the legs.

6. Name the bone found in the upper part of the leg.

7. List major bones of the arms.
8. Name the bone found in the upper arm.
9. List at least three functions of the skeletal system.
10. What is fracture?

63
Unit 14: Muscles
 What are Muscles?

It is because muscles contracted to help you fold your arm.

Muscles are soft tissues found in our body. They cover our bones and help to move
them. Bones and muscles work together to move our body.

Need of Keeping Healthier Muscles

Healthy muscles let us move freely. They also keep our body strong. They help us
enjoy playing, dancing, walking and other activities. Strong muscles also help to keep
our joints in good shape.

Importance of Muscles

Muscles are very important for human body.

1. They help in the movement of human body.

2. They support our body.

3. They help maintain posture.

14.1 Main Groups of Muscles

The muscles of heart and lungs do not work at our will. These are involuntary
muscles. These muscles do not get tired and work continuously. Can you name some
other involuntary muscles?

Differences between Voluntary and Involuntary Muscles

64
 14.2 Major Voluntary Muscles of the Human Body

We use voluntary muscles to perform different activities. Some of the major voluntary
muscles are:

(a) Major Muscles of the Head

The muscles in our head help us move different parts of the face. They also move our
jaw and scalp. There are various muscles in our head. Based on their functions, they
are classified as:

1. Eye muscles

2. Facial muscles

3. Chewing muscles

4. Neck muscles

(b) Major Muscles of the Trunk

Our trunk has a large number of muscles. Some of these muscles are:

1. Pectoralis major (or Chest muscles): These muscles keep the arms attached to the
body.

2. Rectus abdominis (or abdominal muscles): These muscles help in breathing

process.

3. Deltoid (or Shoulder muscles): These muscles prevent joint dislocation.

4. Serratus muscle: This muscle allows the forward movement of arm.

(c) Major Muscles of the Legs

Legs are used for standing, walking, jumping and other work. Major muscles of legs
are:

1. Gluteus medius (or Hip muscles): these muscles provide movement, strength, and
stability to the hip joint.

65
2. Popliteus (or Knee muscles): These muscles allow the body to walk, run and jump.

3. Vastus lateralis (or Thigh muscles): These muscles allow the thigh to move.

(d) Major Muscles of the Arms

The arm’s curved shape comes from its major exterior muscles. These muscles also
give the arm its strength.

The major muscles of an arm are:

1. Biceps

2. Triceps

Both biceps and triceps have opposite functions. When biceps muscle contracts, the
arm bends and triceps muscle stretches. When triceps muscle contracts, the arm is
stretched.

14.3 Functions of Voluntary Muscles

66
Major functions of voluntary muscles are:

1. Produce skeletal movement: Contraction and relaxation of muscles allow the

bones to move.

2. Maintain posture and body position: Good posture depends on the strength of
muscles. A person with strong muscle can maintain upright posture.

3. Stabilise the joints: The muscles around the knee keep the joints in a good shape.
These also protect the knee from injury.

14.4 Accidents of Muscles (Cramp) and First Aid

Muscle cramps are sudden contractions of muscles. These contractions are often
painful. Commonly affected muscles include the back of lower leg, the back of
thigh, and the front of thigh. It is caused due to dehydration and muscle fatigue

First Aid for Muscles (Cramp)

If you have a muscle cramp:

1. Stretch the cramped muscle to increase flexibility.

2. Gently massage the cramped muscle.

3. Drink plenty of water.

4. Take a hot water bath.

14.5 Hygiene of Muscles

For healthy muscles, the following care should be taken:

1. Take good food and pure air.

2. Avoid dangerous games.

3. Sit, walk and stand in a correct posture.

4. Do physical exercise regularly.

67
 FINAL ASSESSMENT

SUR NAME: …………………………………………………

OTHER NAME:
…………………………………………………………………….

CLASS /STREAM :…………DATE : ………………………

ACADEMIC YEAR 2020

PRIMARY FOUR CLASS

STAY HOME PACKAGE BOOKLET

FOR OFFICIAL USE ONLY

SECTIONS MARKS OBTAINS MARKS OUT OF

TOTAL 100

Parent’s comments :
………………………………………………………………

Contact: ………………………. Signature: ………………...

1.All questions are compulsory.

2.Read each question carefully before answering it.

3. Answer the questions in the space provided on this question paper

I. Fill in the blanks with the correct options:

1. Muscles are the ............ found in the body.

(a) Tissues (b) cells

(c) Organs (d) none of these

2. Muscles that work at our will are called ………… muscles.

68
(a) Voluntary (b) involuntary

(c) Cardiac (d) none of these

3. Muscles that do not work at our will are called ………… muscles.

(a) Voluntary (b) involuntary

(c) Cardiac (d) none of these

4. ………… muscle is on the front of the upper arm.

(a) Biceps (b) Triceps

(c) Involuntary (d) None of these

5. ………… are the sudden contraction of muscles.

(a) Cramps (b) Bruise

(c) Cuts (d) None of these

IV. Answer the following questions briefly:

6. List the major groups of muscles of the human body.

……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………
.

7.What are the functions of voluntary muscles?

……………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………
…………

8. What are the causes of muscle cramps?

……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………….

9. List some ways in which we can keep our muscles strong.

I. Fill in the blanks with the correct options:

69
10. Organs which help us to see, hear, smell, taste and feel are called............. .

(a) breathing organs (b) sensory organs

(c) reproductive organs (d) none of these

11. ………… is the sensory organ for touch and feel.

(a) Ear (b) Eye

(c) Skin (d) Nose

12. ………… is the sensory organ of sight

I. Fill in the blanks with the correct options:

13 ....................... tools help us use information and share it digitally.

(a) ICT (b) UPS

(c) DATA (d) Website

14. .................... is a collection of web pages.

(a) Data (b) Website

(c) Digital (d) Analogue

15 The ................. lies behind all other components on your screen.

(a) mouse (b) keyboard

(c) desktop (d) none of these

16. The ............ is a special folder where you can place files and folders you no longer
need.

(a) window (b) home

(c) icon (d) trash

17 ............... is a type of computer program that allows you to perform a particular

task.

(a) Application (b) Text Editor

(c) Calculator (d) Character map

II. Answer the following questions briefly:

70
18. What are the roles of a computer?

……………………………………………………………………………………………………………………………………
…………………………………………………………………………………………….

19 .Differentiate between data and information.

……………………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………….

20. Write the steps to switch on and switch off a computer.

……………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………

End

REFERENCE

 REB-Science Elementary and Technology for Rwandan

Schools Pupil’s Book Primary5 .Laxmi Publications(P)Ltd 2017
 REB-Science and Elementary Technology Syllabus for upper
Primary. P4-P6.Kigali 2015

71