In 1829 Hertz entered the Berlin Academy Challenge to demonstrate Maxwell's electromagnetic waves originated by Helmholtz. His first demonstration, a success, was to prove one of Maxwell's predictions, namely that a magnetic field in an insulating block was equivalent to that in a conductor when subject to electromagnetic oscillations. His second demonstration, also successful, was to show that the relative velocities of electric propagation from an emitting oscillator were the same traveling in a wire as in air, and therefore proved another of Maxwell's predictions. He later demonstrated that the light, heat, and electromagnetic wave motion all behaved as electric waves in agreement with the field force theory of Farady and Maxwell and a denial of Newton's "action-at-a-distance." Proof had been obtained that electromagnetic and light waves behave the same. Hertz and his contemporaries believed that electromagnetic waves in space needed "ether" to support them. Some time later, Michaelson and Morley proved that "ether" did not apply to the propagation of the waves and was not needed.

Was ultraviolet light an agent in touching off sparks at a detector ring spark gap (later identified as the photo-electric effect)? Hertz experimented in Berlin and in 1890 in Bonn, but the vacuum in his experiments was inadequate to minimize the ionization of residual gases which shielded the electric field. With an improved higher vacuum, J. J. Thompson (1856-1940) at Cambridge in 1897 did identify the stream of charged particles (later called "electrons" by Stony).

A bone malignancy led to Hertz's death in 1894 on New Year's Day at age 37.

Building on the discovery of a "decoherer" to improve reliable and sensitive detection of electromagnetic waves in 1894 by Sir Oliver Lodge, Gulielmo Marconi (1874-1937) of Bologna, Italy, son of an Italian father and an Irish mother, was able to successfully experiment with Hertzian waves. On December 12, 1901, Marconi achieved wireless communication across the Atlantic and began radio.