Radio Waves and the Electromagnetic Spectrum
There is some science that you can see in action. For example, chemical changes and reactions. But, what about what is not visible to the human eye? What about science such as cells and radio waves. In today’s blog, we’ll explore the science behind modern communication technology. Plus, give a rundown of the rest of the electromagnetic spectrum.
What are Radio Waves?
Radio waves are a type of electromagnetic radiation with the longest wavelengths on the spectrum. In a vacuum, they travel at the speed of light. Meanwhile, in the Earth’s atmosphere, they move at a close, but slightly slower, speed. The sound that is heard is energy.
So, how does this happen? Well, radio waves are generated by charged particles undergoing acceleration, such as electric currents. Lightning and astronomical objects emit naturally occurring wavelengths. Additionally, they are part of the radiation released by all warm objects. We should note that they waves cannot be heard by the human ear or create acoustically.
Instead, transmitters artificially generate radio waves. Then, using antennas, radio receivers pick up the wavelengths. We can find this occurring in:
- fixed and mobile radio communication
- broadcasting
- radar and radio navigation systems
- communications satellites
- wireless computer networks
What’s more, different frequencies of radio waves (different wavelengths) have different spreading characteristics in the Earth’s atmosphere. For example, long waves bend around obstacles like mountains and follow the Earth’s ground waves. Meanwhile, shorter waves reflect off the Earth’s upper atmosphere and return to earth beyond the horizon in skywaves. Because of this difference, and that shorter wavelengths travel on a line of sight, these frequencies’ distances are limited to the visual horizon.
Discovery
James Clerk Maxwell first predicted radio waves by mathematical work in 1867. Now called Maxwell’s equation, he proposed that a couple electric and magnetic field could travel through space as an ‘electromagnetic waves”. What’s more, he offered that light consisted of these waves with a very short wavelength.
In 1887, Heinrich Hertz demonstrated the reality of Maxwell’s prediction. He showed that radio waves exhibition the same wave properties of light such as:
- standing waves
- refraction
- diffraction
- polarisation
Later, in 1894, Guglielmo developed the first practical radio transmitters and receivers. This communication began commercial use around 1900.
The Electromagnetic Spectrum
Radio waves exist on something called the Electromagnetic Spectrum. This is the range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies. Let’s have a look at it from those with the longest wavelengths to the shortest.
- Radio Waves. These wavelengths are the longest and, as we’ve discovered, are used for communication purposes.
- Microwaves. A short wavelength of radio waves, these frequencies can penetrate into materials and deposit their energy below the surface. Thus, why we use them to heat up our food.
- Infrared Radiation. There are three parts. Far-infrared which are close to microwaves. Mid-infrared which is what the human skin at normal body temperature radiates. Near-infrared which is detected by some type of photographic film.
- Visible Light. The part of the spectrum the human eye is most sensitive to and thus, can see.
- Ultraviolet Radiation. Emitted by the sun, sunburn is an example of the disruptive effects of UV radiation on the skin cells.
- X-Rays. They are used to see thorough objects with thicknesses less than the equivalent to a few metres of water.
- Gamma Rays. They help sterilise food and seeds and are occasionally used in radiation cancer therapy.
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