Electromagnetic energy (EM) is a remarkable phenomenon, that has in recent times, been considered ubiquitous to human existence. If this sounds like a foreign scientific concept to you, you’ll be surprised to learn just how much you interact with it.
It permeates every aspect of everyday life. It’s the light that illuminates everything you see. It’s the Wi-Fi you use to connect to the internet. It’s how you communicate with loved ones using your smartphone.
It’s an inescapable part of the world you live in. Here are 5 electromagnetic energy examples in daily life you probably never knew about.
Check out this guide to protecting your home from EMFs.
1. Ultraviolet Light
Ever wondered what makes black-light posters glow in the dark? Or, why you get a tan when you lay out in the sun? Well, ultraviolet light, or UV for short, is responsible for this. So, what is UV anyway?
It’s a type of EM radiation that comes from the sun. Transmission occurs in waves at different frequencies and wavelengths. In the electromagnetic spectrum, it falls between visible light and X-rays and has frequencies ranging between 8 × 1014 Hz to 3 × 1016 Hz.
Its wavelengths range between 10 nanometers to 380 nanometers (1 nanometer is equivalent to one-billionth of a meter). UV-light can be classified as UVA, UVB, or UVC in order of decreasing wavelengths. Here are some applications of UV light in everyday life.
Synthesis of Vitamin D
The human body doesn’t naturally produce vitamin D. UVB stimulates the synthesis of this vital vitamin, which is responsible for the absorption of calcium to keep your bones healthy and strong. Low vitamin D levels in the body cause soft bones, which become brittle and, in some cases, painful.
To reap the full benefits of UV light, you have to go outside for exposure since window glass absorbs it. However, too much exposure can cause skin cancers. So, aim to get the optimum amount that won’t be detrimental to your health in the long run.
Disinfection
Modern-day technology allows you to wash and dry your clothes effortlessly. You don’t even need to venture outside to do it. What you probably don’t know is that hanging your washing outside to dry in the sun leaves them cleaner than if you dried them using your energy-hungry drier.
This can be attributed to the disinfection and sterilization effects of UVB. A large number of bacteria and viruses that may be present in your laundry get deactivated when exposed to UVB.
This sanitizing property of UV light has been artificially exploited to produce UVC, which has a myriad of applications. For instance, it is now used to sterilize medical equipment, treat drinking water, and even deactivate harmful microbes in sewage treatment plants before the clear effluent flows into a water body.
UVC disables the DNA strands in bacteria and viruses, effectively rendering them inert. That way, they can’t multiply or reproduce.
Fluorescence
Fluorescence refers to the ability of certain substances to absorb the energy contained in UV light and convert it into visible light. Here’s how.
A fluorescent element absorbs some form of EM energy. In most cases, this happens to be UV light. It then promotes the electrons to a higher energy state. While the electron is at this excited-level, it loses some of its energy in the form of heat, effectively returning it to its ground state energy level.
In the process, it emits a photon, which is a discrete package of light. The human eye perceives this emitted photon as a fluorescent glowing color. Substances whose electrons are mobile and have a substantial difference in energy between the ground and higher-level states are more likely to fluoresce.
Beta-carboline is an example of a fluorescent chemical that’s naturally-occurring in scorpions. Nonetheless, fluorescent chemicals are also artificially engineered with a wide range of applications in glow sticks and pathogen detection. The latter provides a quick and efficient way to detect the presence of E.coli in contaminated food.
Curing
In the early 19th century, UV radiation was previously referred to as “chemical rays.” This was because it had the uncanny ability to convert the chemical composition of certain substances.
An instance of this was its ability to harden particular glues quickly. This changing chemical effect of UV light is called “curing.”
2. Microwaves
You’ll find microwaves on the higher frequency end of the electromagnetic spectrum between radio and infrared light. They have a wide range of day-to-day applications, some of which include radar, communications and, what most people know it for, cooking.
Microwaves are distinguished from radio waves mainly by the different technologies that are used to access them. They have large frequencies ranging from 1GHz to 300GHz. Their wavelengths, on the other hand, are very short and range between 30cm and 1mm.
This makes them ideal for conveying signals over a wide range of frequencies without the danger of interference or overlap. Aerial antennas are the devices used to broadcast microwave signals and receive them.
Here are some common uses of microwaves.
Communications
The origin of the technology dates back to World War 2 when it was developed during secret military radar research. Microwaves are used in point-to-point communications to transmit information. This is commonly used in video, voice, and data transmission in both digital and analog formats.
Magnetrons and klystrons are the two most popular devices used in the generation of microwaves. They produce low powered signals, which are then amplified using a MASTER (Microwave Amplification by Stimulated Emission of Radiation).
These are then modulated for communication purposes. Modulation in telecommunications is the process whereby one or more properties of a high-frequency EM wave – referred to as the carrier signal – are varied with a modulating signal.
The latter contains information that is to be transmitted. This could be in the form of an analog audio signal or a digital bit-stream, which is then embedded in another signal that can be physically transmitted.
Read: Top Ways to Protect Yourself from 5G Radiation
Radar
Another popular application of microwaves is radar. “Radar” was initially an acronym for Radio Detection and Ranging.
Its origin dates back to the pre-World War 2 period when British radio engineers realized that they could bounce short-wave radio signals off distance vessels like an aircraft or ship. They further established that they could use highly sensitive directional receiver antennas to determine the precise location and presence of those very vessels.
Today, radar is an independent word that describes the microwave (or radio) systems used to detect the location and presence of air-crafts and ships. Additionally, they can also provide information on the vessels’ relative distance and speed.
Microwave Heat Sources
Perhaps the most well-known application of microwaves is to heat food. After World War 2, Percy Spencer discovered the thermal effect of microwaves purely by accident. As he was working on an active radar set, he noticed that the chocolate bar he had in his pocket began to melt.
With his curiosity piqued, he began to experiment with popcorn before moving on to an egg. The results were astonishing. The popcorn popped, and the egg exploded (which pretty much what happens if you try to heat an egg in a microwave).
Armed with this knowledge, he harnessed this energy to create a working prototype in 1945, for which he went on to file a patent application in October of the same year. This technology was used to develop the modern-day microwave oven. Its mode of operation is fairly straightforward.
When you place food in the microwave, the EM radiation polarizes the food molecules. As a result, they attempt to align with the EM field which causes them to rotate. In the process, they collide with other food molecules.
This constant collision increases its kinetic energy, which is released in the form of heat. That’s how your food heats up so fast.
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3. X-Rays
As a type of EM energy, X-rays are best known for their ability to allow people to see through human skin and reveal the underlying exoskeleton. They are classified into soft X-rays and hard X-rays.
Soft X-rays have wavelengths of approximately 10 nanometers, which is quite short. This places them between UV light and gamma-rays in the electromagnetic spectrum.
Hard X-rays, on the other hand, have wavelengths of about100 picometers (1 picometer is equivalent to one-trillionth of a meter). This category of X-rays occupies the same area of the electromagnetic spectrum as gamma rays, which poses the question: What is the difference between hard X-rays and gamma rays?
The answer to this question has to do with how each of them is generated. Accelerated electrons give rise to X-rays, whereas atomic nuclei in nuclear reactions are responsible for generating gamma rays.
The modern-day applications of X-rays go beyond exoskeletal imaging. More focused and powerful beams are now used to kill cancerous tumors, image microscopic biological cells, and inanimate structural components like cement.
X-Ray Sources
X-rays are generated by bombarding a beam of electrons containing copious amounts of energy, into a gallium or copper atom. When they collide, the electrons in the s-shell, which (the inner shell), get flung out of their orbit.
This causes the atom to become unstable and as a result, attempts to get back to a state of equilibrium. Therefore, an electron that’s in the 1p shell of the atom drops in to fill the gap. To do this, it has to release some energy in the form of an X-ray.
When this energy is released, it goes off in all directions. Due to this lack of focus, it makes it quite difficult to use the ray as a high-energy source. That’s where a synchrotron comes in.
A synchrotron is a particle accelerator whose sole purpose is to accelerate charged particles such as electrons inside an enclosed circular path. Anytime a charged particle is accelerated, it emits light. The type of light depends on the energy that the particle contains and the magnetic field that accelerates it around the circular path.
Synchrotron electrons are usually accelerated to near the speed of light. So, as you would expect, they release a powerful beam of focused X-ray energy.
Applications of X-Rays: Imaging
Originally, X-rays were used in bone imaging. Based on the type of film that was used at the time, it was easy to distinguish bones from a patient’s soft tissues. Since then, technology has advanced in leaps and bounds paving the way for more precise focusing systems and detection methods that are more sensitive than they were in the past.
This has made it possible to identify subtle differences in bone and tissue density as well as distinguish other fine details using much lower X-ray exposure levels than was previously possible.
Now, Computed Tomography (CT) uses multiple X-ray images to generate a 3D model of a particular part of the human or animal anatomy. Additionally, the same technology can be used to reveal the 3D images of the structural interiors of engineering components.
You’ll find other imaging applications of X-rays in the transportation sector. It’s an efficient method of conducting security inspections of passengers, luggage, and any other cargo that’s in transit. It provides real-time visualizations of the package content and anything that passengers might be carrying.
Radiation Therapy
Radiation therapy or radiotherapy, as it is commonly called uses X-rays in the treatment of cancer. Ionizing radiation from X-rays obliterates cancerous tumors by administering a sufficient dose of radiation to zap the abnormal cells.
X-ray energy works by stripping atoms and molecules of their electrons. This alters their properties. In some cases, it’s been known to cause cancer. However, controlled amounts of radiation, carefully administered in the right quantity, are also used to fight the disease.
4. Gamma Radiation
Gamma-rays are a form of EM radiation. They have frequencies of more than 1,018 Hz and wavelengths that are less than 100 picometers. It is often difficult to differentiate between gamma rays and hard X-rays, given that they overlap in the electromagnetic spectrum.
In certain disciplines like astrophysics, for instance, the two types of EM waves are differentiated by drawing an arbitrary line in the spectrum. Here, rays that are above a certain wavelength are categorized as X-rays,whereas those of a shorter wavelength, fall on the other side of the arbitrary line and are classified as gamma rays.
While both X-rays and gamma rays contain sufficient energy to cause irreversible damage to living tissue, the greater majority of cosmic gamma rays emanating from outer space are blocked by the Earth’s atmosphere.
Gamma-Ray Sources
Gamma rays are generated in one of four ways. The one thing all methods have in common is that the rays are produced as a byproduct of nuclear reactions.
Nuclear Fusion
Ever looked up at the sky and wondered where the sun draws its power from? Well, the answer to this lies in nuclear fusion. Here’s how that works.
When four hydrogen nuclei, which are essentially protons, are fused under extreme temperatures, they merge to form a helium nucleus with two nuclei and two protons. The new nucleus is usually about 30% of the size of the four protons that were present at the onset.
The resulting difference in mass is given off as energy. This gave rise to Einstein’s famous E=mc2 equation. Two-thirds of that energy is given off as gamma rays with the rest emitted at neutrinos. Neutrinos are weakly interacting particles with almost zero mass.
Nuclear Fission
In this method, a single heavy nucleus is split into two almost equal lighter nuclei. To achieve this, heavy nuclei like plutonium and uranium are bombarded with other particles to give rise to smaller elements like strontium and xenon.
The resulting particles are then used to bombard other larger nuclei paving the way for a nuclear chain reaction. Since the combined mass of the resulting particles is less than that of the original nucleus, the difference is converted into energy and released as gamma rays, smaller nuclei, and neutrinos.
Alpha Decay
The phrase “alpha decay” refers to a process where the nucleus of a large and unstable atom, sheds two neutrons and two protons in a packet referred to as an alpha particle. This process gives off a Helium-4 nucleus, effectively reducing the original particle’s atomic weight by 4 and its atomic number by 2. The process leaves the nucleus with excess energy, which is then released in the form of a gamma-ray.
Gamma Decay
In this type of radioactivity, a heavy unstable atom dissipates excess energy spontaneously. As a result, it emits it in the form of a gamma-ray. Unlike alpha decay, however, the charge and mass composition of the original atom remains unchanged.
Gamma Ray Applications: Cancer Treatment Therapy
Gamma-ray therapy is sometimes used as a course of treatment for cancer patients. It works by damaging the DNA of the abnormal cells, therefore, obliterating the cancerous tumors in a patient.
The downside to this is that gamma rays also damage the surrounding tissues. So, great care and precision must be taken when administering this treatment. An effective way to do this would be to use a linear particle accelerator to direct multiple beams of gamma rays onto the target tumor. Gamma Knife and CyberKnife therapies employ this principle, where highly targeted radiosurgery is called for.
5. Radio Waves
These are a form of EM energy best known for their application in communication technologies like radios, televisions, and mobile phones. The electronics receive radio waves before converting them into mechanical vibrations in the devices’ speakers to generate sound waves.
Radio waves make up a relatively small part of the electromagnetic spectrum compared to its counterparts. However, they have the longest wavelengths ranging between 1 millimeter and well over 100 kilometers. On the flip side, their frequencies are also the lowest ranging between 3 kHz and 300 GHz.
Just like a farmer would split their farmland to get the highest yield during harvest time, the radio spectrum is an equally limited resource that needs to be allocated efficiently among its multiple users. The National Telecommunications and Information Administration is the body charged with doing this in the US.
Read more about the health dangers of being near cell towers.
Radio Wave Bands: Applications
The radio spectrum comprises different bands according to their frequency and wavelength range. These are categorized into low to medium frequencies, higher frequencies, and shortwave radio.
Low to Medium Frequency Radio Waves
The lowest of the radio waves in the electromagnetic spectrum is the Extremely Low Frequency (ELF) waves. They have a long-range wavelength, which makes them useful in penetrating large bodies of water as well as, thick rock when communicating with submarines and inside caves or mines, respectively.
Lightning is a powerful natural source of ELF and VLF (Very Low Frequency) radio waves. The waves emitted bounce back and forth between the earth’s surface and the ionosphere. This is partly why radio signals traveling to satellites are distorted during a lightning storm.
Marine and aviation radio, as well as commercial amplitude modulation (AM) radio all, constitute Low Frequency (LF) and Medium Frequency (MF) radio bands. AM radio has a long-range, particularly at night since the ionosphere refracts waves better at that time of day. However, if the signal is blocked by a metal-walled building, for instance, the sound quality will be reduced.
Higher Frequencies
The higher frequencies region comprises the High Frequency (HF), Very High Frequency (VHF) and Ultra-High Frequency (UHF) bands. They generally use frequency modulation (FM) to embed data or audio signals onto the carrier wave.
In doing this, the signal amplitude remains constant while the frequency varies at a higher or lower rate corresponding to the magnitude of the data or audio signal transmitted. Applications of higher frequency bands in daily life include Global Positioning Systems (GPS), FM radio, broadcast television sound, and cellphones.
Shortwave Radio
The shortwave spectrum has several segments, some of which are dedicated to popular broadcasting stations like the Voice of America and the BBC. Shortwave signals can be transmitted over thousands of miles from their point of origin since they bounce off the ionosphere and rebound over long distances.
References
Michael F. Holick, The Influence of Vitamin D on Bone Health Across the Life Cycle, The Journal of Nutrition, Volume 135, Issue 11, November 2005, Pages 2726S–2727S, https://doi.org/10.1093/jn/135.11.2726S
