The 7 Electromagnetic Wonder Waves

The 7 Electromagnetic Wonder Waves

Read through the following passages to find the correct information about each wave. Fill in the chart as you read.

1.  Radio Waves

These electromagnetic waves have the longest wavelengths and the lowest frequency. The wavelength can be as short as a football fields and can reach lengths as much as the diameter of the earth!

Radio waves were first discovered in the late 1880’s by Heinrich Hertz. He found that there could be an electrical charge transferred between to metal coils (transmitters). This caused particles to be excited electrically and changed their place of motion changing its magnetic properties. With his discoveries, scientists were able to perceive different waves like radio and later related to other astronomical objects like the sun.

Common day things that release radio waves are broadcast waves like the ones used for AM and FM radio and television programs. The broadcast station sends out radio waves and your radio or TV antenna picks up the wave and turns it into an electrical signal and then converted to the picture or sound you see and hear.

Other radio emissions that are observed must have special radio telescopes. The energy released from black holes, the sun and even quasars galaxies away.

http://missionscience.nasa.gov/ems/05_radiowaves.html

2.  Microwaves

Microwaves are just what their name implies, smaller waves. These waves are the smallest type of radio waves, however in comparison to the smallest of the electromagnetic waves, they are still relatively large. The actual size is 300 MHz to 300GHz (so smaller than a football field and bigger than a strand of hair). Their frequency is just barely faster than radio waves.

You are most familiar with microwaves in its relation to the household electronic appliance to heat up your food. The appliance works by sending microwaves to your food, which then excites the water and fat molecules inside. As these molecules start moving faster and faster, they release thermal energy and heat up.

Other microwaves that you can apply to life, relate to the weather man and a speeding ticket.

Meteorologists (weathermen/women) use radar imaging devices from satellites. The term radar stands for radio detection and ranging. The images of hurricanes, cold fronts, warm fronts… were all detected from these microwave detecting satellites.

How often have you or your family used a GPS to find your location or get directions. Well that GPS (global positioning system) uses microwaves!

A radar gun also uses the microwaves to send those radio waves at moving objects to find their speed. It can be used to find the speed of a baseball or moving car. (Sometimes resulting in a speeding ticket L).

http://missionscience.nasa.gov/ems/06_microwaves.html

3.  Infrared Waves

Light your alcohol burner and feel the heat rise up as radiation. That visible heat you feel is infrared radiation. The wavelengths of this wave range from 1000microm - .7microm (basically the size of a human hair). The frequency is higher than radio and microwaves.

Often times these rays are felt as heat and they can also be called heat rays. Heat lamps are just one example of a device that gives off infrared rays.

Most things do give off some amount of infrared rays. This is in the form of radiation. Warmer objects give off more infrared rays than cooler objects. An infrared camera can capture how much energy is being released from these infrared rays. Military and firefighters use infrared cameras to see people they need to find in situations when vision is limited.

Longer wavelengths of infrared waves can even include the remote to an electronic device. Some cell phones and digital cameras even have these infrared wavelengths.

http://missionscience.nasa.gov/ems/07_infraredwaves.html www.mass.gov

4.  Visible Light

All electromagnetic waves are classified as light but the light that we can actually see is called visible light. Special cells in our eyes filter these wavelengths into the colors that we see. Some creatures, such as bees, have a greater capability of seeing more of the spectrum of light with higher frequencies.

The wavelengths for visible light ranges from 700 nm to 400nm (about as thick as a soap bubble). The frequency is just lower than ultraviolet rays.

Visible light seems white but can be refracted with a prism to see all the colors of the rainbow. Violet and blue colors have the shortest wavelengths and reds and oranges have the longest wavelengths.

http://missionscience.nasa.gov/ems/09_visiblelight.html

5.  Ultraviolet Rays

Ultraviolet rays (UV rays) have a higher frequency than visible light and a wavelength of 400 nm – 10nm (about the size of a virus).

These waves come from the sun and have been sub classified as UV-A, UV-B, and UV-C. You’ve probably heard of sunscreens or sunglasses that are UV-A and UV-B proof. UV-C rays are most harmful however our atmosphere absorbs most of these rays before they reach the surface of the earth.

Some UV light is necessary for humans because it provides vitamin D for the body to give you strong bones and teeth. Too much UV exposure however causes damage to your cells and has been linked to cancer and vision damage.

Tanning beds used to give a person a bronzed colored body use UV rays that penetrate the skins cells. Although it gives one a darker skin tone, it also damages cells and the FDA has linked tanning bed usage to faster aging skin and cancer.

Other evidences of UV rays being emitted in our atmosphere are shown with the Northern Lights. In certain times of the year, particles collide with different element gases in the atmosphere and give off different colors resulting in the beautiful light show in the sky.

http://www.fda.gov/forconsumers/consumerupdates/ucm186687.htm

http://missionscience.nasa.gov/ems/10_ultravioletwaves.html

6.  X-Rays

You’ve heard of x-rays before but did you know that those waves sent through the machine to view bones or teeth are about the size of an atom. The actual size of the wavelength ranges from 3nm - .003nm. The frequency of the wave is almost as high as a gamma ray.

These x-rays were discovered in 1895 by Wilhelm Roentgen. He found that if you sent these waves through different body parts, then you could see detailed images of the bones inside. X-rays work by sending these waves through a body part which then transfer to a special film on the other side. The x-rays are absorbed more by denser tissue like bones. Thus shadows appear on the film where the bones are because they block the x-rays.

Too much exposure to x-rays causes damage to cells. That’s why when you go to the dentist and they take an x-ray, they put a lead apron on you to block the rays from penetrating your body.

Other uses of x-rays are used for engineering. Engineers can send x-rays through a building to see if there are any cracks or leaks in the structure of a building.

http://missionscience.nasa.gov/ems/11_xrays.html

7.  Gamma Rays

Gamma Rays have the shortest wavelength and the highest frequency. The size of this wave is about the size of a nucleus in an atom. Because they are so small and have such a high frequency, they can penetrate more things than any other wave.

Most of these waves from the sun and other objects in space do not pass through our atmosphere, however there are things on Earth that can emit these harmful waves. Some radioactive products and nuclear reactions produce gamma rays.

Although gamma rays can be harmful, they can also be used for medicinal purposes such as treating cancer. The rays can penetrate the body and kill the mutated cells. To view certain parts of the body, doctors can inject a radioactive substance that gives off gamma rays into a patient. Then using a gamma ray detector, they can see the organs and tissues needed to be observed.

http://missionscience.nasa.gov/ems/12_gammarays.html