Radio Waves Proven (Hertz)
In the 1880s Heinrich Hertz built a spark transmitter and receiver and showed that the waves Maxwell predicted are real, travel at the speed of light and reflect, bend and polarise like light.
Open in the interactive tree →At Karlsruhe, Hertz used a dipole with a spark gap, fed by an induction coil, as transmitter and a wire loop with a tiny spark gap as receiver. He made standing waves by reflecting them from a zinc plate, bent them with a prism of pitch, and showed that they are polarised and travel at the speed of light. In 1887 he also saw that ultraviolet light makes sparks jump more easily, the first sign of the photoelectric effect, and he saw no practical use for his waves; from 1894 Guglielmo Marconi built on Hertz's experiments and turned them into wireless telegraphy.
Prerequisites
- Electromagnetism1831-1865Hertz tested Maxwell's prediction of electromagnetic waves
Unlocks
- Radio (Wireless Telegraphy)1895Marconi built wireless telegraphy on Hertz's transmitter and receiver
- Photoelectric Effect (Einstein)1905Hertz first saw ultraviolet light help sparks jump, in 1887