Heinrich Hertz's experiments in the late 19th century played a crucial role in demonstrating the existence and properties of electromagnetic waves. At the time, there was a prevailing belief that the phenomenon observed by Hertz was merely an induction effect rather than the propagation of electromagnetic waves. However, with the advancement of scientific understanding and further experimentation, it became clear that Hertz had indeed discovered electromagnetic waves.
Here's how we would explain it today:
Experimental Observations: Hertz's experiments involved the generation of high-frequency oscillating electric sparks, which created rapidly changing electric fields. He observed that these electric fields produced corresponding magnetic fields that propagated through space. This observation indicated that the changing electric fields were not simply inducing currents in nearby conductors (induction effect), but instead were capable of traveling through space independently.
Maxwell's Equations: James Clerk Maxwell, a prominent physicist of the time, had formulated a set of equations that mathematically described the behavior of electric and magnetic fields. Maxwell's equations predicted the existence of electromagnetic waves as solutions to these equations. Hertz's experimental observations were consistent with the predictions made by Maxwell's equations, providing further evidence for the existence of electromagnetic waves.
Wave Properties: Electromagnetic waves exhibit characteristic wave properties, such as wavelength, frequency, propagation speed, and the ability to interfere and diffract. Hertz observed these properties in his experiments, which further supported the wave nature of the observed phenomenon.
Transmission through Space: Unlike induction effects, which are typically confined to nearby conductors, Hertz's experiments showed that the electromagnetic waves could propagate through free space, without the need for physical contact with conductive materials. This ability to propagate through a vacuum, as well as through different media, demonstrated that the observed phenomenon was not solely dependent on the presence of conducting objects.
Based on these subsequent developments and our current understanding, it is clear that Hertz's experiments demonstrated the existence of electromagnetic waves. Today, electromagnetic waves are recognized as a fundamental aspect of nature and form the basis of many modern technologies, including wireless communication, radio, television, and various forms of imaging such as radar and MRI.