A tuning fork is used for tuning instruments. You take the tuning fork, hit it against something and it will give a certain note, depending on the fork. You then tune the instrument using the tuning fork's note as reference.
a wooden surface is better for a tuning fork rather than, say, a metal surface because the wood vibrates less than metal, and doesn't interfere with the vibrations of the fork. rubber is probably the best surface to hit a fork on.
if u hit it on a wooden desk (like a classroom desk) it will vibrate and you can see and feel the vibration of a tuning fork like that. If u touch it ur finger/hands will keep it from vibrating . ur welcum 4 telling u d answer! "peace!"