Notes For All Chapters – General Science Class 6
Sound
1. What is Sound?
Sound is a type of energy that we hear with our ears.
It is made when an object vibrates (moves back and forth quickly).
Without vibrations, there is no sound.
2. How is Sound Produced?
- When you pluck a rubber band, it moves and makes sound.
- When you beat a drum or tabla, the skin vibrates and produces sound.
- In a speaker, the diaphragm moves back and forth to make sound.
3. How does Sound Travel?
- Sound travels in the form of waves.
- It moves through air, water, and solids.
- It cannot travel in a vacuum (empty space with no air).
4. Examples of Sound Travel
- Sound travels fastest in solids, slower in liquids, and slowest in air.
- You hear a knock on a wooden table better when you place your ear on it.
- A train’s sound can be heard from railway tracks before it arrives.
5. What is Noise Pollution?
- Noise pollution happens when there is too much loud and unpleasant sound.
- It is harmful to humans, animals, and the environment.
6. Causes of Noise Pollution
- Honking of vehicles
- Loudspeakers and firecrackers
- Machines and factories
- Aeroplanes and railway engines
7. Effects of Noise Pollution
- Hearing problems (can damage ears).
- Lack of concentration (disturbs studies and work).
- Stress and irritation (makes people angry and tired).
8. How to Reduce Noise Pollution?
- Do not blow horns unnecessarily.
- Keep TV and music at a low volume.
- Use silencers in vehicles.
- Plant trees to absorb noise.
- Follow rules about loud noise in schools and hospitals.
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