Hertz is a unit of measurement that denotes the number of times per second that something vibrates. The hertz unit was named after the German physicist Heinrich Rudolf Hertz, who conducted groundbreaking experiments in electromagnetism during the late 19th century.
Today, hertz is used to measure all sorts of things, from the frequency of electromagnetic waves to the speed of computer processors.
While most people are familiar with using hertz to describe how often something happens (such as how many times per second a light bulb flashes), it can also be used to describe other things like wavelength and amplitude.
For example, when sound waves travel through the air, they compress and rarefy the air molecules around them. The number of times/cycles per second that this compression and rarefaction occurs is called the frequency, and it is measured in and symbol is (Hz) – just like Hertz!