The frequency is a measurement used in physics and technology and is specified 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 unit of time. The frequency thus describes 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. tones that the human ear recognizes, but also electromagnetic waves, cosmic radiation or gravitational waves.