Science Projects And Inventions

YOU NEED:

• A saw
• A playing card

The sound of a reed instrument like a clarinet or a saxophone, is the result of the vibration of a reed. Vibration of the air creates sound in wind instrument like violins, comets and trombones. Again in musical instruments like violins or cellos the sound is created because of friction between the bow and the string. The pitch of the sound depends on how fast the vibration is .  This is amply demonstrated if the edge of a playing card is rubbed against the teeth of a saw. If you rub the card slowly it produces sound at a lower pitch which increases in crescendo when the card is moved faster.

HOW DOES IT WORK?

There is no difference between the manner in which vibrations are created when a card is rubbed against the cutting edge of the saw and when the bow causes friction against a violin string. The friction between the edge of the card and the edge of the saw creates vibrations, which in turn produces the sound.