Who was the German physicist that first demonstrated the existence of electromagnetic waves?

The German physicist who first demonstrated the existence of electromagnetic waves is Heinrich Hertz. He conducted a series of experiments in the late 19th century that confirmed the theoretical predictions made by James Clerk Maxwell about the presence of electromagnetic radiation. Hertz generated and detected radio waves in his laboratory, which provided crucial evidence for Maxwell's equations and the wave nature of electromagnetic radiation.

Hertz’s experiments involved the use of oscillators and receivers that allowed him to produce and observe electromagnetic waves, confirming their properties such as reflection, refraction, and polarization. This groundbreaking work laid the foundation for the development of modern telecommunications and wireless technology, as it proved that electromagnetic waves could travel through space.

Maxwell, while critical in formulating the theoretical framework that described electromagnetic phenomena, did not physically demonstrate the existence of these waves. Therefore, Hertz's experimental validations are what solidified his role in the history of physics as the first to demonstrate electromagnetic waves.