The electromagnetic waves must be surprise their discoverers. The reason is that electromagnetic waves are a waveform that has the largest role than any other waveforms.
Almost all types of electromagnetic waves are discovered by different person. The discoverers of electromagnetic waves, of course, also have a unique history. Let’s see!
History of Electromagnetic Waves Discovery
What is electromagnetic waves? Electromagnetic waves are energy-carrying waves that travel in magnetic and electric fields. Divided into several types. However, sometimes the boundaries between EM waves are uncertain. Here’s the history of its discovery.
1. Discovery of Radio Waves
Mathematical prediction of radio waves was done by James Clerk Maxwell. This mathematical prediction led to the discovery of radio waves. In short, his mathematical theory predicts that a combination of waves in an electric field and a magnetic field can propagate as “electromagnetic waves”. Maxwell later also proposed the theory that visible light actually comprises electromagnetic waves with very short wavelengths.
The German physicist, Heinrich Hertz, demonstrated the prediction regarding electromagnetic waves by the 1880s. He demonstrates it experimentally in his laboratory, producing radio waves. These waves exhibit the same wave properties as light, which can undergo refraction, diffraction, polarization, and can form standing waves.
Guglielmo Marconi, an Italian inventor, then developed the first radio transmitter and receiver in 1894 to 1895. For his work, he received the Nobel Prize in physics. Radio communication then was used commercially in the 1900s. And in 1912, the modern term “radio wave” replaced the original term “Hertzian wave”.
2. Discovery of Microwaves
Several experiments in the 1890s had actually produced microwaves. One of them is by Heinrich Hertz, the previous discoverer of electromagnetic waves, in the same demonstration he discovered radio waves. The experiment concentrated on producing short radio waves and microwaves.
However, microwaves only came into practical use in the 1940s and 1950s because of inadequate equipment and resources. Experiments for communication in 1931 led to further experiments using microwaves. The experiment was done by transmitting telephone, telegraph and facsimile data between Dover, England and Calais, France.
Since these wavelengths are shorter than microwaves, a new term needs to be used. These waves were originally called “short waves” and “ultra-short waves”. However, the term microwave then came into use in 1931.
Microwave technology developed very well before and during world war 2. Microwave used as radar in the 1930s. And in world war 2, the use of microwaves in radar technology helped the allied block’s communication on the battlefield, which led to victory.
Microwaves were then widely exploited commercially after world war 2. one advantage of microwaves is the very large frequency range (bandwidth), this happens because the frequency of microwaves is quite high). In fact, microwaves can carry tens of thousands of phone calls in a single beam.
Therefore, in the 1950s and 1960s, the telephone and television networks between cities and continents (US and Europe) were commercially used. The launch of the first communications satellite in the 1960s was also supporting the usage. And in 1964, cosmic microwave background radiation was discovered, which is one of the grand discoveries to date.
3. Discovery of Infrared Light
Sir Frederick William Herschel discovered the infrared light in 1800. He wanted to prove his hypothesis about how hot a sunlight color is at different temperatures. He then directs sunlight through a prism so that it breaks down into various colors (rainbow colors).
When he measured the temperature, the closer to the red color, the hotter the recorded temperature. However, when he tried to measure the temperature just outside of the red color that seemed to have no light, it actually showed the hottest temperature among the previous measurements.
He later discovered that this invisible light can reflect, refract, absorbed, and transmitted exactly as visible light. We know this invisible light as infrared light or infrared radiation. This discovery marks the first evidence that there is an invisible light.
4. Discovery of Visible Light
It is rather difficult to describe who the discoverer of electromagnetic waves on this one is, because visible light is a type of electromagnetic radiation that has accompanied humans throughout history. However, the results of human thought or theory about “what visible light really is?” are developing time after time. The following is a brief description of the ‘history of human acquaintance with visible light.
Early Theory and Particle Theory
At first, the theory of visible light was very simple. Light is thought to only come from fire. Until then, Sir Isaac Newton put forward the theory of light as a particle in the 1660s. Newton’s theory can predict the phenomenon of reflection well, but misguided in predicting refraction that light slows down in a denser medium because the force of gravity is stronger.
Then in 1690, with a mathematical equation, Christian Huygens published the theory of light is a wave. He suggested that light propagates as a series of waves that propagate in a medium called luminiferous ether. And light travels more slowly in a denser medium.
There are also scientists such as Thomas Young, Leonhard Euler, and Augustin-Jean Fresnel who also supported and contributed to this theory. In wave theory, light can interfere with each other just like sound waves and other waves. In addition, different wavelengths of light also caused different colors. This theory can also more easily explain the phenomena of diffraction and polarization in light.
Electromagnetic Radiation Theory
Then, in 1845, Michael Faraday discovered that the plane of polarization of light rotates when light passes through a strong magnetic field in a transparent medium, this is known as the Faraday effect or Faraday rotation. This is the first evidence that light is related to electromagnetism. Then, in 1847, he proposed that light is a high-frequency electromagnetic vibration that propagates without a medium.
James Clerk Maxwell then discovered that the propagation of electromagnetic waves travels at a constant speed equal to the speed of light that has been previously measured. From this, Maxwell concluded that light is a form of electromagnetic radiation, which he stated in 1862.
The quantum theory of light then appeared in the 1900s. You can read more about it at quantum theory.
5. Discovery of UV Rays
Johann Wilhelm Ritter discovered UV ray in 1801, a year after the discovery of infrared light. At that moment, he observed that the invisible rays beyond the purple light darkened the silver-chloride-soaked paper faster than the purple light. Then it was discovered that UV light can kill bacteria in 1878. In addition, UV light with a wavelength below 200 nm was discovered in 1893 by Victor Schumann. This UV light is called vacuum ultraviolet because oxygen strongly absorbed it in the atmosphere.
6. Discovery of X-Rays
Before it was actually discovered, X-rays were simply unknown radiation that had emerged from previous experiments. On November 8, 1895, Wilhelm Röntgen experimented with a cathode tube and accidentally produced an invisible beam. For his discovery, he received the Nobel Prize in physics. The discoverer of this electromagnetic wave called it X-rays, because he did not know what radiation it was. However, in some languages, X-rays is also called Röntgen rays.
7. Discovery of Gamma Rays
Paul Villard, a French chemist, was the first to observe Gamma Rays in 1900. He was studying the radiation emitted by radium. Paul Villard had previously discovered beta radiation/rays (β) in 1896 and alpha radiation (α) in 1899. Paul Villard later discovered radiation in which he called gamma rays (γ), to match the previous radiation.
This radiation (gamma rays) has unique characteristics from the previous two radiations. Unlike the other two rays, Villard discovered that gamma rays cannot (at least very difficult to) be deflected by magnetic fields. Gamma rays also have a stronger penetrating ability than the three radiations.
Gamma rays were originally thought to be particles that have mass, like alpha and beta rays. In 1914, Rutherford and Edward Andrade proved that gamma rays can reflect on the surface of crystals, which means that gamma rays are electromagnetic radiation. Rutherford and Andrade also measured the wavelength of gamma rays and found them to be similar to X-rays, only that they were shorter.
Gamma rays are also found in space. One of them is the phenomenon of gamma-ray bursts.
Each type of electromagnetic beam has a unique history. From the weakest, radio waves, to the strongest, gamma rays. The discoverers of electromagnetic waves (EM radiation) are:
- Radio Wave. By Heinrich Hertz (1880s)
- Microwaves. By Heinrich Hertz. (1890s)
- Infrared Rays. By Sir Frederick William Herschel (1800).
- Visible light. Since the dawn of human civilization. Theory as particles by Sir Isaac Newton (1660s), theory as waves by Christiaan Huygens (1690), and theory as electromagnetic radiation by Michael Faraday (1845).
- UV rays. By Johann Wilhelm Ritter (1801).
- X-rays. By Wilhelm Röntgen (1895).
- Gamma rays. By Paul Villard (1900).