Sound is a form of energy that is produced by vibrations. These vibrations create sound waves, which travel through a medium, such as air or water, to reach our ears. Sound waves are a series of compressions and rarefactions, where compressions are regions of high pressure and rarefactions are regions of low pressure. This back-and-forth motion of particles in a medium is what allows sound to propagate.

Sound waves have several key properties. One of these properties is frequency, which refers to the number of vibrations or cycles per second. The unit of frequency is hertz (Hz). For example, a sound wave with a frequency of 440 Hz is perceived as an A note in music. Another important property is wavelength, which is the distance between two consecutive compressions or rarefactions. Amplitude, on the other hand, represents the maximum displacement of particles from their resting position in a sound wave.

Now, let's take a look at an example to illustrate these concepts. Imagine a guitar string vibrating at a certain frequency. When plucked, the string creates sound waves that travel through the air. These sound waves consist of compressions and rarefactions, with the frequency determining the pitch, the wavelength determining the perceived note, and the amplitude determining the volume of the sound.