Science Class 4 - Force Work-And-Energy Notes

Force, Work and Energy

Welcome to the chapter on Force, Work and Energy for Class 4. In this chapter, you will learn what force is, how work is done, and why energy is important. By the end of this chapter, you will be able to explain how things move, how work is done, and where we get energy from!

Introduction

We use force, do work, and need energy every day. When you push a door, lift your school bag, or run in the playground, you use force and energy. Let’s learn more about these important ideas!

What is Force?

Force is a push or a pull. We use force to move things, stop things, or change their direction.

• Pushing a swing is using force.
• Pulling a drawer is using force.
• Kicking a ball is using force.

Effects of Force

• Force can move an object.
• Force can stop a moving object.
• Force can change the shape of an object.
• Force can change the direction of a moving object.

What is Work?

Work is done when force moves something. If you push a box and it moves, you have done work. If it does not move, no work is done.

• Lifting a book is work.
• Writing in your notebook is work.
• If you push a wall and it does not move, no work is done.

What is Energy?

Energy is the ability to do work. We need energy to run, jump, play, and even think!

• Food gives us energy.
• The sun gives energy to plants.
• Electricity is a form of energy.

Sources of Energy

• Sun
• Food
• Wind
• Water
• Fuels like petrol and diesel
• Electricity

Fun Activity: Find the Force!

Make a list of things you push and pull every day. Try to notice when you use force and when you do work!

Summary

• Force is a push or pull that can move things.
• Work is done when force moves something.
• Energy is needed to do work.
• We get energy from food, the sun, and other sources.

Practice Questions

1. What is force?
2. Give two examples of work you do every day.
3. Name two sources of energy.
4. What happens if you push a box and it does not move?
5. Why do we need energy?

Challenge Yourself

• Draw and label a picture showing force, work, and energy in action.
• List three things you do that need energy.

Did You Know?

• The sun is the main source of energy for all living things on Earth!
• Machines use energy to help us do work faster and easier.

Glossary

• Force: A push or pull.
• Work: When force moves something.
• Energy: The ability to do work.
• Source: Where something comes from.

Answers to Practice Questions

1. Force is a push or pull.
2. Lifting a book, writing, running (any two).
3. Sun, food, wind, water, electricity (any two).
4. No work is done if the box does not move.
5. We need energy to do work and stay active.

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Notice how you use force, do work, and need energy every day!