The phonograph is a device, invented in 1877, for the mechanical recording and reproduction of sound. In its later forms, it is also called a gramophone, or, since the 1940s, a record player. The sound vibration waveforms are recorded as corresponding physical deviations of a spiral groove engraved, etched, incised, or impressed into the surface of a rotating cylinder or disc, called a "record". To recreate the sound, the surface is similarly rotated while a playback stylus t

Cell phones, radio, television, satellite communication, WLAN - it is hard for us today to imagine a world without the technology of electromagnetic waves. And yet, the man who first created, detected and studied them was born just 160 year ago on February 22, 1857. Heinrich Hertz grew up in Hamburg, Germany, where his father was a lawyer and senator of the city of Hamburg. After school, he prepared to be a civil engineer, but he was fascinated by mathematics and physics, and