Learning About Light Energy: The Electromagnetic Spectrum
The word "electromagnetic spectrum" may sound like something scientific that is used on the Star Trek Enterprise as it travels through space checking out the secrets of the universe. However, electromagnetic spectrum or EM is nothing more than a categorized system of different types of radiation put into a group. To understand this spectrum, you must understand the different types of radiation as well as understand what radiation is and how it works. To begin this scientific journey, the first thing we find out is that radiation is energy that travels and spreads out as it moves or generates.
There are several forms of radiation, and some of them you are already familiar with. For instance, there is radiation known as visible light. You will find this type of radiation in your home lighting fixtures, like a desk lamp which you do your homework by. Radiation comes through such things as radio waves. You will find this happening every time you turn on your music box to listen to your favorite rap or hip-hop music. Other forms of radiation that come from the EM are microwave, infrared, ultra violet light, x-rays and gamma rays.
When it comes to the energy waves, the energy emitted is measured in forms of low to high energy-levels. You will find low level energy in such things as a transistor radio and for a high energy supplier you are looking at something nuclear that emits or gives off gamma rays.
Below, we will discuss each of the radiations that make up the Electromagnetic Spectrum.
Radio Wavelength
Out of all the wavelengths on the electromagnetic spectrum, the radio waves have the longest wavelengths. How big or long they are depends upon their usage, for some can be measured to be the length of a football field and other radio waves are much smaller in length.
Whenever you watch your favorite TV program or talk on your cell phone, it is radio waves that bring the signals to these electronic devices. These wave lengths come through antennas from your local TV station or through a satellite dish if you are using a cable company for your TV entertainment. When it comes to your device working, you will not see a picture or be able to text or chat on your cell phone if a signal is not being transmitted to the source. And FYI- between your TV, radio, and cell phone, it is the cell phone that radiates the smallest radio waves.
When we look up at the sky with our eyes, we can see the clouds, the stars and see the brightness of the sun without using radio waves to get the image. However, astronomers can see further when they use tools that emit radio waves, tools such as the radio telescope. With this device, scientists are able to get images of objects and matter on other planets; for instance, carbon monoxide gases on the Milky Way have been observed and documented through radio waves and the radio telescope.
Microwave Wavelength
If you think you have never experienced or witnessed the effects of what this energy source is, think again. Microwaves are part of the electromagnetic spectrum that lets us see earth from space. This is the energy that is used in giving weather reports, when the newscaster gives warnings of bad weather approaching. Weathermen televise images of storms like that of Katrina or Andrew and do so by using Doppler-Radar imaging that captures images in real-time or as it is occurring and what we see are the colored spots of the storm, from the outer band to the eye of the storm, it all shows up.
Microwaves are listed at a higher range on the radio spectrum and they come in different wavelengths. They are grouped into categories of bands. There are the C-band and the L-bands to name a few. C-bands have a medium length of energy, and they can penetrate through elements such as snow, rain, dust, clouds and smoke. Once the C-band penetrates, it can show the surface of the earth and what's going on in it. The L-band on the other hand can penetrate a dense forest and bring back information that measures the soil and moisture of places like the rain forest. In other words, the purpose or the job of microwaves is to send information from one place to the other. Some microwaves are used in heating our foods, that's when we zap them in the microwave oven for a few minutes. However, the energy used in microwave cooking is measured in centimeters, which are only a foot in length. But, when it comes to certain amounts of radiation, like the Cosmic Microwave Background radiation, we have a huge mass of radiation that covers not only the earth's atmosphere, but the entire universe.
Infrared Wavelength
Another section of the electromagnetic spectrum is that of infrared wavelengths. This energy light source sits between the visible and microwaves sections of the spectrum. There are 3 types of wavelengths attached to the infrared and they are the near, far, and middle. The far infrared wavelengths are the size of a pin head, so they are tiny. The infrared which is near are much larger, they are microscopic in size, meaning that they are the size of a cell.
The radiations in the far infrared wavelengths are something we experience each day when we get heat from the sun warming the earth. When you walk barefoot on the sidewalk in the summer, that heat or warmth that you feel comes from infrared. With the far infrared, you can feel the wavelengths on your skin. However, the near infrared is the opposite; you can't feel them because they aren't hot. Near infrared is created with a shorter wavelength. An example of a near infrared item is that of the remote control apparatus that operates your TV set.
Even though we may sometimes feel the effects of infrared light, human beings cannot see the light source; however, if you were a rattle snake with sensory pits, you would be able to detect other warm blooded predators even if they were hiding in a dark secluded hole in the ground. Other sources that give off infrared light are the sun, stars, and far away galaxies.
Infrared imaging allows us to view clouds and their structures, giving detailed information. Such information lets us know that dark clouds are warm, while white fluffy clouds are cool, which means the closer a cloud is to the ocean, the warmer it is.
Visible Wavelength
When it comes to being able to see electromagnetic waves, human beings can only see the visible light waves, which is another section of the spectrum. When we see these waves, what appear to our eyesight are magnificent colors of red, orange, yellow and indigo or the colors of a rainbow to be more precise. Each of these colors is a wavelength with red being the longest and violet being the shortest in wavelengths. All of these colors blending together as one create white light.
Whenever you see a rainbow, it happens because water vapor had entered the prism and separated the wavelengths.
The sun is a natural source of visible light waves. Light bulbs are another source of this wave length in action. There are many Hinkley chandelier lights that are dressed with light bulbs that display visible wavelength. Hinkley chandeliers have become the leading lighting fixtures that combine visible light waves with progressive design elements.
There are two main instruments that can detect visible light waves from great distances and they are a telescope and a satellite. With these instruments, you can see the earth's surface and the bounties of the sky.
Ultraviolet Wavelength
On the electromagnetic spectrum is another area of energy called the ultraviolet waves. This light source has short wavelengths and this too is a wavelength that we cannot see with the human eye. However, if you were a bumble bee buzzing around a flower, you would be able to see the UV waves or light. There are 3 ranges to this particular wavelength and they are near, far, and extreme ultraviolet. What distinguishes them from each other depends upon how strong the radiation energy levels are and the wavelengths.
Although the sun gives off light using all the wavelengths of the spectrum, it is the ultraviolet waves that harm the skin when there is too much exposure to sunlight. Ultraviolet waves causes sunburns and skin cancer when we over do it in the sun trying to get a tan. Another important factor to note is the fact that there are some ultraviolet rays that get through to the earth's atmosphere, but most of these waves are blocked by such gases as the ozone.
Today, we have satellites that scientists use to study ultraviolet wavelengths. One of these satellites is the Hubble Space Telescope. It gathers information from a small portion of UV light. However, for the big tough jobs of studying the extreme UV, NASA uses the Extreme Ultraviolet Explorer Satellite.
For the last 17 years, studying both the far and near ultraviolet regions; the International Ultraviolet Explorer has been used, gathering data so that astronomers can learn of the effects of this wavelength on the galaxies of the universe.
X-ray Wavelength
At least everyone at some point in their lives has had the experience of having an x-ray taken. This happens when your doctor wants to take a look at the inside of your body, when they want to view your bones. The images that come from x-rays are established through high levels of energy. X-rays have smaller wavelengths which produces high energy levels. Although the x-ray region is part of the electromagnetic spectrum that produces all these different waves, the x-ray actually behaves more like a particle than a wave because of the smallness of the wavelengths. And in regards to the earth's thick atmosphere, x-rays cannot penetrate the surface of the earth from outer space like ultraviolet waves can do. However, x-rays performed in hospitals or at the dentist office lets the physician see shadows of bones or teeth that been projected and captured on film.
In X-ray Astronomy, x-ray detectors attached to satellites lets the scientist see inside such things as the black holes in the universe because such objects as the black hole emits x-ray waves. Other emitting x-rays that are found in outer space are the sun, stars, remnants of super nova and comets.
X-rays travel at the speed of light and in straight lines, and since they are much more energetic, they are able to travel through objects that that ordinary light waves cannot penetrate.
Gamma Rays Wavelength
The last region on the electromagnetic spectrum is that of the gamma rays. Of all the wavelengths within the spectrum, it is the gamma rays that have the smallest wavelengths and the most energy. You can find gamma rays in radio active atoms and nuclear explosions. Because of its powerful charge, gamma rays can kill living cells. Doctors use this source of energy for medical purposes, using the highly energetic rays to kill bad cells in cancer patients.
To detect gamma rays in the atmosphere, it takes balloons and spacecrafts like the Explorer Xl Satellite to go above the atmosphere to get documentation of this powerful energy in action.
The first person to discover gamma radiation was Henri Becquerel, a French physicist. Because of his study, we found out that gamma rays travel at the speed of light and they can only exist as long as they have energy. When the energy is gone or all used up... the gamma ray dies.
Gamma rays are the primary concern for public safety in the event of a radiological emergency. It is highly hazardous because it is a source of dangerous energy that people cannot see or feel when the radiation comes in contact with the body. Therefore, it is wise to become familiar with gamma radiation warning symbols that tell you to stay way, or stay out from a particular dangerous area that is known or suspected of having gamma radiation.
For more information on this topic, please see the websites below.
Article Written by Colby McTwain
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