The length of a sound wave is called the wavelength, and the number of vibrations per second is called the frequency.

Here's the breakdown:

* Wavelength: The distance between two consecutive crests (or troughs) of a sound wave. It's measured in units like meters or centimeters.

* Frequency: The number of complete cycles of a sound wave that occur in one second. It's measured in Hertz (Hz).

Think of it like this:

* Wavelength: How stretched out or compressed the wave is.

* Frequency: How quickly the wave is oscillating.

They are related: Higher frequency means shorter wavelength, and lower frequency means longer wavelength.

Let me know if you have any other questions!