Our ears hear. We all know that. The pick up vibrations first and then change them in to nerve pulses. The ear drum is the major hearing part of our ear.

All substances can have sound traveling through them. Sound can pass through solid stuff too! But it doesn't get from one thing to another to well. Alot of the time sound bounces back off the walls or floor. This is an echo.

Amplify means to make a sound louder. Decibels are how loud sound is. An amplifyer at its simplest is a big cone. You can also use the cone to hear stuff louder by putting it up to your ear. Thunder is 110 decibels.

A wave of sound can be changed from electrical energy into sound energy and than back again. It does this so it can be carried over long distances such as the telephone. When you're on a telephone, the sound waves turn into electrical pulses so that they can travel through the telelphone wire. These are like the nerve pulses that carry noises all the way from our ears to our brains.

A phonograph is a very early recorder of sound. The way it recorded was kind of odd when you consider the way we record sound today. There was a needle in the middle of a drumhead which was coated in wax or tinfoil. The needle would bounce up and down and record by making grooves on the surface.

Bats can't see very well but as you might have guessed, they can hear very well. They hear ultrasound. Ultrasounds are high-pitched sounds and we can't hear them; they are way too high. But bats like to use it. That's the only way they can get around. All they do is squeek and if the sound bounces back, they know that there's a wall in front of them. They can even judge the distance to the wall.

A transmitter, particularly a radio transmitter, can send sounds all over the place. It's sort of like a telephone because it changes electrical impulses into radio waves. Radio receivers can pick up the waves and then back into sound they go.

Music is part of sound and every sound has an individual pitch: low or high and this pitch is depending on the shape of the sound wave. Each one is music is a different musical note. If you put all of these together and arrange them low to high or high to low, you have a musical scale. Instruments come in many different sizes and shapes and you might think, Òhow do some have to do with sound?" They all make noise but how? It's very simple! They all make sound by making the air vibrate. Like brass instruments, you play a recorder by changing the length of the piping by pushing down keys or covering up to holes.