What happens when a tuning fork is dipped into water?

When a tuning fork is dipped in water, the frequency of the sound it produces changes. This is because the water molecules interact with the tines of the tuning fork, causing them to vibrate at a slower rate. The change in frequency is proportional to the density of the water, so the tuning fork will produce a lower pitch in denser water.

This phenomenon is known as acoustic impedance. Acoustic impedance is a measure of the opposition to the flow of sound waves. The higher the acoustic impedance, the greater the opposition to sound waves. Water has a higher acoustic impedance than air, so it is more difficult for sound waves to travel through water. This is why the tuning fork produces a lower pitch in water.

The change in frequency can be used to measure the density of water. This is a technique that is used in hydrology to measure the density of water in rivers, lakes, and oceans.