Published on 02/16/2008

Whether you are playing an instrument, speaking, or just making a noise, the way the sound is made, and the way it travels, is exactly the same. The difference between music and noise is that musical sounds are organized into patterns with pitch and rhythm. While noise is usually made up of random, disorganized sounds.

Science of Sound

HOW SOUND TRAVELS: A sound is made when something vibrates and makes particles in the air next to it vibrate. The air particles pass the vibration from one to another. You can describe a sound by showing it on a graph. The shape is called a sound wave. Different sounds have different shaped sound waves. The number of times a sound wave vibrates each second is called frequency. A high note has a high frequency.

SOUND WAVES: The look of a sound wave varies according to what is making the sound. These sound waves are all produced by different instruments.

ELECTRONIC INSTRUMENTS: A lot of bands use electronic instruments, such as drum machines and keyboards. These sorts of instruments use a computer chip to store and reproduce sound waves.

Science of Sound

STORING SOUND: A chip doesn't store the sound itself: it stores numbers which describe a sound wave. The numbers indicate the height of the wave measured at regular intervals.

DRUM MACHINES: Drum macines are electronic devices that store pre-set sounds made by percussion instruments, such as cymbals, drums or maracas. You choose a sound and then play a rhythm by tapping on pads. You can also record a rhythm and play it back, so you can play another instrument alongside the rhythm. Rhythms can also be made faster or slower. Most drum machines have pre-set rhythms. These can be useful if you don't want to make up your own.

PLAYING WITH SOUNDS: A keyboard is designed to store the sound waves produced by musical instruments, but it can also reproduce other sounds, such as a bird tweeting. This is done using a machine called a sampler. Some keyboards have sampled sounds. Once the sound has been stored, you can play tunes with it. You can even alter the sound by reversing it or making it echo. You can have great fun experimenting with sounds which have been stored on a keyboard. Imagine playing Mozart with a bird tweeting for each note!"