Final answer:
A drum makes a sound by vibrating when it is hit, and to produce a lower pitch, the drum skin needs to be loosened.
Step-by-step explanation:
When a drum is hit, it makes a sound through vibrations. These vibrations occur because hitting the drum skin causes it to vibrate. The air then carries these vibrations as sound waves. If a drummer wants to make the sound of a drum give a note of lower pitch, they would need to loosen the drum skin. This is because a looser skin vibrates with a longer wavelength, producing a lower pitch, according to the relationship between the size of an instrument and the pitch of the sound it produces.