What makes a sound high-pitched or low-pitched?

The pitch of a sound is determined by its frequency, with high frequency sounds being high-pitched and low frequency sounds being low-pitched.

In more detail, sound is a type of wave that travels through a medium, such as air or water. These waves are created by vibrations, which cause the particles in the medium to move back and forth. The frequency of a sound wave refers to the number of these vibrations that occur in a given amount of time. This is usually measured in hertz (Hz), with one hertz being equal to one vibration per second.

When a sound wave has a high frequency, it means that the vibrations are happening quickly. This results in a high-pitched sound, like the squeak of a mouse or the note of a flute. On the other hand, when a sound wave has a low frequency, the vibrations are happening more slowly. This results in a low-pitched sound, like the roar of a lion or the note of a tuba.

The human ear is capable of hearing a wide range of frequencies, from about 20 Hz to 20,000 Hz. However, our ability to hear different frequencies can vary depending on factors such as age and exposure to loud noises. For example, as people get older, they often find it harder to hear high-frequency sounds.

In addition to frequency, the pitch of a sound can also be affected by its amplitude, or the size of the vibrations. Larger vibrations can make a sound seem louder, but they don't change its pitch. Instead, the pitch is solely determined by the frequency of the vibrations. This is why, for example, a loud low note on a piano still sounds low, even though it's louder than a quiet high note.