Video title: Sound is energy

What's wrong with this city in India?

Mumbai, India

What can you hear?

There's no sound.

Here's what Mumbai should sound like.

Sound is produced by lots of things in cities, in the countryside, in our homes... anything that makes a sound is called a sound source.

sound source

But what is sound?

What is sound?

Sound is a form of energy.

sound
form of energy

When something makes a sound, the sound energy flows away from the source in waves.

sound waves

Sound waves travel in all directions.

sound waves
travel in all directions

That's why you can hear a noise if the source is above or below you...

Behind or in front of you.

A whisper is a low-energy sound.

It can only be heard from a few metres away.

The high-energy sound from a rocket travels a lot further.

high-energy sounds
travel further than low-energy sounds

A thunderclap has an enormous amount of energy.

It can be heard from many kilometres away...

Hopefully giving you enough time to take shelter before the thunderstorm arrives.

Sound is a form of energy.

Understand that sound is a form of energy created by vibrations.

Learning points

• Sound is a form of energy.
• Sound travels in waves away from the source.
• Sound waves travel in all directions.
• Low-energy sounds are quiet.
• High-energy sounds are loud.

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