Re: When I pluck a stick it makes a sound, how does it do this?

Sound is caused by vibrations in the air: the air compresses and spreads 
out in the direction of movement:

|| |  |   |  | || |  |   |   | || |  |   |  | || --->SOUND

The more frequntly the air vibrates, the higher pitched the sound is. The 
higher the difference in pressure between the compressed and spread-out 
parts, the higher the volume.
When you tap the stick, the air around it begins to vibrate, just as when 
you pluck a guitar string, its vibrations cause a sound wave.
Try plucking sticks of different length. The longer the stick, the longer 
it takes to vibrate, the lower the frequency, the lower the pitch of the 
resulting sound.