Notes For All Chapters – General Science Class 6
Work and Energy
What is Energy?
Energy is the ability to do work.
Without energy, we cannot do anything.
We get energy from food.
Types of Energy
1. Mechanical Energy
It is the energy of movement.
Two types:
a) Potential Energy – Stored energy (e.g., water in a dam).
b) Kinetic Energy – Energy of motion (e.g., a running car).
2. Heat Energy
The sun gives heat energy.
It helps in cooking food, keeping us warm, and drying clothes.
3. Light Energy
The sun gives light energy to help plants make food.
We use light bulbs to see in the dark.
4. Sound Energy
We hear sound when something vibrates (e.g., clapping hands, playing music).
Loud sound can even break glass.
5. Chemical Energy
Found in food, wood, and fuels (like petrol).
Burning wood gives heat and light because of chemical energy.
6. Electrical Energy
It is used in fans, lights, TVs, and refrigerators.
It comes from power stations or solar panels.
Transformation of Energy
Energy can change from one form to another.
Example:
In a dam, water’s potential energy → changes to kinetic energy → moves a turbine → produces electrical energy.
Sources of Energy
There are two types of energy sources:
1. Conventional (Non-renewable) Energy (can finish one day)
Coal, petrol, diesel, natural gas, wood.
These take millions of years to form and cannot be replaced quickly.
2. Non-conventional (Renewable) Energy (never finishes)
Solar energy (from the sun).
Wind energy (from moving air).
Hydroelectric energy (from falling water).
Tidal energy (from ocean waves).
Atomic energy (from uranium and thorium).
Why Should We Save Energy?
Fossil fuels (coal, petrol) will finish one day.
Using renewable energy like solar and wind is better.
Ways to save energy:
- Switch off lights and fans when not needed.
- Use solar energy.
- Walk or cycle instead of using a car for short distances.
Green Energy
Green energy does not pollute the environment.
Examples: Solar, wind, and hydro energy.
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