CBSE Class 3 Science Worksheet N

Forces

Objective _Students will be able to know about force.

_ Students will be able to list types of simple machines.

_ Define the word Friction and gravity.

_ Students will be able to know air and water resistance.

A force _ is a push or a pull.

A fraction_ is the force between surfaces that are touching.

Gravity pulls objects towards the centre of the earth.

Air resistance and water resistance

Air and water resistance slows down moving objects.

To travel faster through the air, things need to be streamlined.

Simple machines

Simple machines _ turn small forces in to big efforts.

Machines make it easy for us to do work.

Types of simple machines

1. A liver – is a simple machines, made from along pole and a pivot.
2. A pulley _ is a rope running through a wheel.
3. Gears_ are wheels with teeth that fit together.

Summary questions for section eight

Fill in the blank space

1. ________________ Surfaces creates lots of fraction.
2. A rope running through a wheel is called ________________.
3. Sharks and fish can move quickly in water because they have ____________ bodies.
4. _____________ travels through air slowly.
5. ______________ surfaces don’t create much fraction.

Define the following items

1. Gravity _____
2. Force ________
3. Gears _________

Give short answer

1. Why do we have good grip on our shoes?
2. Which type of force doesn’t need contact between objects?
3. List and define types of simple machines.
4. A force can make things
5. What sort of surface should a ramp have to prevent people slipping? ____________
6. What is produces, if two surfaces rubs together? __________________
7. What shape should an object be, in order to travel faster through the air? _______________
8. Which force slows things down in water? ____________________
9. What is the name of the force that pulls objects down towards the center of the earth? _______________
10. Why is a lever a useful machine?
11. Name a simple machine that would help you to lift a heavy object Using a rope.

V. Answer the following questions. 
1. What is air made up of ? 
2. Describe the process of formation of soil from rocks.

VI. Give reason. 
1. Very few plants grow on a sandy beach.

VII. Life Skill. 

Soil is a very precious resource and we need to do our best to take care of it.
There are many ways to conserve soil.

Put a tick for the right options.
a. We should build as many roads and buildings as possible. ______
b. Prevent soil pollution. ________
c. Throwing garbage anywhere. ______
d. Planting trees to prevent erosion of soil . _______

Q.1 Unscramble the following words:
1. NTAUARL. ___________ 2. MIMSOA ___________
3. GLLIS ___________ 4. ARI HELOS. ___________
5. LNUGS ___________ 6. BARETEH ___________
7 . SEDES. __________ 8. AMINALS. ___________
9. PANTLS. ___________. 10. BDRIEG. ___________

Q.2 Name the following.
1. The thing like animals, plants and human which can move, breathe , feel, eat and reproduce are called . ___________
2. The things which cannot move, breathe , feel, eat and reproduce are called ___________
3. The things made by humans are called___________
4. To gently move your hand over something.____________
5. The things that are the gift of nature. .____________

Q.3 Give two example for each:
1. Non-Living things. _____________. ______________
2. Living things. ____________. ______________
3. Natural things. _____________. _____________
4. Man made things. ____________. ______________
5. Animals that breath through lungs. _______________. ______________.
6. Animals that breathe through gills. _______________. ______________.
7. Insects that breathe through air holes _______________. ______________

New Words ( copy New words twice in notebook)

1. Mountain 2. Plains 3. Desert 4. Paddy 5. Humus
6. manure 7. Clayey soil 8. Loam soil 9. Fossils

Define the following terms:
1. Humus: parts of dead plants and insects present in the soil.
2. Manure: it contain cow dung and decaying leaves which makes the soil fertile.
3. Paddy: it is a rice crop.
4. Fossils: the remains of living organisms that died millions of years ago and were pressed deep under the rocks.

Answers
1. The action of the sun, the rain, and the wind breaks up the rocks to make soil. It takes millions of years for this to happen.
2. The size of the particles of soil are different in different types of soil due to the present of humus , clay, sand and stone in the soil.
3. We can show that soil contain moisture by performing the following activity.
Put some soil in a small tin cover it with a lid and heat the tin on a low flame. After opening the lid, we can see drops of water on that soil has moisture in it.

(Draw figure 3.3 on page 28.)

4. Following are the three different types of soil
• Sandy soil
• Clayey soil
• Loam soil

5. Farmers add manures to soil to increase the fertility of soil.

Extra questions

Q.6 Why clayey soil is sticky?
Ans. Clayey soil is sticky because it holds lot of water.

Q.7 Why loam is considered as the best soil for plants?
Ans. Loam is the best soil for plants because it contains ir, water and humus which makes the soil fertile.

Please click on below link to download CBSE Class 3 Science Worksheet N