what happens when a vibrating tuning fork is dipped in water?

When you vibrate a tuning fork in air, it produces a sound. Sound is basically a disturbance of the source (tuning fork here) which is carried forward by the particles in the medium. When air is the medium, sound propagates through the air molecules which are far apart. There is sufficient intermolecular space that allows faster propagation of sound. However, when ths sound wave ( disturbance of medium) is allowed to pass through a liquid such as water, it slows down. This is naturally because now the water molecules which are closer to each other have lesser freedom to move. Thus, the sound slows down.
@ Aryan,  Basant: Good!