Frequency is a measure used in physics and technology and is given in the unit Hertz (Hz). It indicates how often a process is repeated within a period of time. In the case of oscillations and waves, the frequency indicates how many periods are passed through per time unit. The frequency therefore refers to the number of oscillations per second. The faster the particles oscillate, the higher the frequency. There are many different types of frequencies. For example, sound events, i.e. sounds that the human ear perceives, but also electromagnetic waves, cosmic radiation or gravitational waves.