Interference of Sound – Tuning fork

In this slide, we shall discuss the amplitude and frequency of sound waves using an example of different tuning forks.

At concert pitch A, the tuning fork vibrates back and forth 440 times per second. Its frequency is therefore 440 Hz.

If the vibrations are weaker, the wave crests and troughs become smaller.

In other words, the maximum deflection, or the so-called amplitude, decreases. The sound becomes lower. The wavelength, which is represented with λ, remains the same.

If the vibrations are stronger, the wave crests and troughs increase, and the amplitude increases with them. The sound becomes louder. The wavelength λ does not change.

If the tuning fork is heavier, it vibrates slower. That means its frequency decreases, and the pitch becomes deeper. The wavelength λ increases.

If the tuning fork is lighter, it vibrates quicker. That means its frequency increases, and the pitch becomes higher. The wavelength lambda decreases.

The sound wave propagation speed c remains constant at about 340 metres per second. It is equal to λ · f.