Birthday of Heinrich Hertz (1857) — Measuring Electromagnetic Waves

Heinrich Hertz was born in Hamburg on February 22, 1857. Between 1886 and 1889, he became the first person to demonstrate the transmission and reception of electromagnetic waves, confirming Maxwell's theoretical prediction of 1865. His key measurement was the wavelength: using a resonating loop, he measured the distance between wave crests and multiplied by frequency to obtain the wave's speed — exactly the speed of light. The unit of frequency, the hertz (Hz), is named for him. When asked about the practical uses of radio waves, he replied: 'Nothing, I suppose.' Within fifteen years, Marconi was transmitting radio signals across the Atlantic.