Imagine you have a toy car. To make it move, you need to push it. Or think about when you eat food — you get the power to run, jump, and play. That “power” is called energy.
Definition in simple words:
Energy is the ability to do work or make things happen.
Without energy, nothing can move, change, or grow.
Example:
A light bulb glows when it gets energy from electricity.
Our bodies move when we get energy from food.
Why is Energy Important?
Energy is all around us and we use it every day.
It helps us:
Move and play
Keep warm in winter
See in the dark
Cook food
Travel from one place to another
Without energy, life would be still and cold — no light, no motion, no sound!
Sources of Energy
Energy can come from many different sources.
We can divide them into two main types:
Renewable Energy (comes from sources that do not run out)
Solar Energy — from the Sun
Wind Energy — from the wind
Water Energy (Hydro Energy) — from moving water
Geothermal Energy — from heat inside the Earth
Biomass Energy — from plants and waste
Example: Solar panels on rooftops use sunlight to make electricity.
Non-Renewable Energy (comes from sources that can run out)
Coal
Oil (Petroleum)
Natural Gas
Nuclear Energy (from uranium)
Example: Cars often run on petrol, which is made from oil — but oil is limited and can finish one day.
Forms of Energy
Energy can appear in different forms.
Light Energy
Energy that helps us see things.
Example: The Sun, bulbs, and candles give light energy.
Heat Energy
Energy that makes things warm.
Example: Fire, the Sun, and a stove produce heat energy.
Sound Energy
Energy we hear as sound.
Example: Drums, guitar, and a person talking produce sound energy.
Mechanical Energy
Energy of movement.
It has two types:
Kinetic Energy — energy of moving objects.
Example: a rolling ball.
Potential Energy — stored energy.
Example: a stretched rubber band.
Electrical Energy
Energy from electricity that powers machines and devices.
Example: Fans, TVs, and mobile phones use electrical energy.
Chemical Energy
Energy stored in substances.
Example: Batteries, food, and fuels like petrol.
Nuclear Energy
Energy stored in the nucleus of atoms.
Example: Used in nuclear power plants to produce electricity.
Energy Transformation
Energy can change from one form to another.
Example 1: In a light bulb — electrical energy changes to light and heat energy.
Example 2: In our body — chemical energy from food changes to movement and heat.
How Do We Use Energy in Daily Life?
Activity | Energy Used | Example Source
Cooking food | Heat energy | Gas stove, electricity
Playing music | Sound & electrical energy | MP3 player, speaker
Riding a bicycle | Mechanical energy | Muscles (food energy)
Watching TV | Electrical & light energy | Power from outlet
Heating a room | Heat energy | Heater, fireplace
Saving Energy — Why and How?
We should use energy carefully because:
Some sources can run out.
Making energy can cause pollution.
Saving energy saves money.
Ways to Save Energy:
Switch off lights and fans when not in use.
Use energy-efficient bulbs (LEDs).
Walk or cycle for short distances instead of using a car.
Turn off taps to save water — water needs energy to be cleaned and pumped.
Use solar energy when possible.
Fun Facts About Energy
The Sun is the biggest source of energy for Earth.
Energy cannot be created or destroyed — it only changes from one form to another (Law of Conservation of Energy).
Lightning is a natural form of electrical energy.
Your body is like a small power plant — it changes food into energy to keep you alive!
Summary
Energy is the power to do work.
It is everywhere and in many forms like light, heat, sound, mechanical, electrical, chemical, and nuclear.
Some sources of energy are renewable (like sunlight, wind) and some are non-renewable (like coal, oil).
We must use energy wisely to protect our planet and ensure it is available for the future.
