When you pour a glass of water, why does the pitch of the sound of the water going into the glass get higher?

Question

When you pour a glass of water, why does the pitch of the sound of the water going into the glass get higher?

In: Physics

Answer 1

The sound bounces around in the air at the top of the glass and the dominant frequency is directly influenced by the size of the space. Larger spaces can allow for larger wavelengths (i.e. lower frequencies). So as you decrease the volume of air by filling the glass, the pitch goes up.