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Explain what sound is

 

What it is
Sound is something you detect with your ears &endash; you can hear it.

You can also feel sound because sound is vibration.

Sound changes with the speed of the vibration.

The vibration makes sound waves which travel really well through the air, but they can travel through just about anything; water, wood, metal, plastic.

A slow vibration makes a low sound, and fast vibration makes a high sound. (Ask your teacher to show you how this works on a guitar!)

In space there is no noise because sound vibrations need air to travel through and there is no air in space.

Sound waves travel through the ground and metal train rails. North American Indians would put their ear to the ground to listen for the sound of horse hooves.  Cowboys listened to the railway lines to hear when a train was coming.

Put your fingers on your throat then say some tongue twisters. (Peter Piper, She Sells Sea Shells, and any others you know) Can you feel the vibration?  That is the movement of your vocal cords. Now try it with your fingers on your lips and then your nose.

Make a rubber band guitar with a box or plastic container and several rubber bands of different lengths.  Smaller rubber bands will have to stretch further &endash; do they make a different sound?

Hold a blown-up balloon about 10 cm away from the speaker of your radio or stereo. Can you feel anything?  Try turning up the volume a little, what happens?  Why does the balloon vibrate?

Put rice/rice bubbles on the top of the speaker and watch what happens when you turn the volume up a little.