Question #8383a

1 Answer
Apr 6, 2017

The vibrating fork is pushing against air molecules which push other air molecules, producing the wave.

Explanation:

This doesn’t work in a vacuum because there is no matter to interact with. In normal air (or other gas atmospheres or liquids) the physical movement of the tuning fork ‘hits’ the air molecules and sets them in motion.

The fork itself is designed to continue oscillating at a particular frequency based on its materials of construction and geometry. Striking it on a hard surface causes a movement, or perturbation, from its normal ‘rest’ state to a stressed, higher energy state. It then tries to return to its rest (minimal energy) state. It cannot do that in one cycle, and thus a “wave” is created in the air by the cyclic movement of the tuning fork as it loses the energy adsorbed from the impact to the surrounding atmosphere.