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All types of radiation travel AT THE SPEED OF LIGHT- but they have different wave lengths. The shorter the wavelength, the more the wave/particle can penetrate solid objects. The frequency is the number of times it takes a wave crest to pass a point in one second. Each color of visible light has a different frequency although this is not shown on this chart.

1. Color the visible light portion of the electromagnetic spectrum with colored pencils.

2. Complete the following chart by identifying the seven main types of radiation labeled in the diagram above and by explaining the uses we have found for each. Use the handout on the EMS and intranet site: http://observe.ivv.nasa.gov/nasa/education/reference/emspec/emspectrum.html

Type of Radiation	Uses	Frequency	Is this type visible to human eyesight?
1 Gamma Rays
2 X Rays
3. Ultraviolet Rays
4. Visible light
5. Infra-red waves
6. Microwaves
7. Radio waves

Electronic Spectrum Information for Chart:

Radio waves are used to transmit radio and television signals. Radio waves have wavelengths
that range from less than a centimeter to tens or even hundreds of meters. FM radio waves are
shorter than AM radio waves. For example, an FM radio station at 100 on the radio dial (100
megahertz) would have a wavelength of about three meters. An AM station at 750 on the dial
(750 kilohertz) uses a wavelength of about 400 meters. Radio waves can also be used to create
images. Radio waves with wavelengths of a few centimeters can be transmitted from a satellite or
airplane antenna. The reflected waves can be used to form an image of the ground in complete
darkness or through clouds.

Microwave wavelengths range from approximately one millimeter (the thickness of a pencil lead)
to thirty centimeters (about twelve inches). In a microwave oven, the radio waves generated are
tuned to frequencies that can be absorbed by the food. The food absorbs the energy and gets
warmer. The dish holding the food doesn't absorb a significant amount of energy and stays much
cooler. Microwaves are emitted from the Earth, from objects such as cars and planes, and from
the atmosphere. These microwaves can be detected to give information, such as the temperature
of the object that emitted the microwaves.

Infrared is the region of the electromagnetic spectrum that extends from the visible region to
about one millimeter (in wavelength). Infrared waves include thermal radiation. For example,
burning charcoal may not give off light, but it does emit infrared radiation which is felt as heat.
Infrared radiation can be measured using electronic detectors and has applications in medicine
and in finding heat leaks from houses. Infrared images obtained by sensors in satellites and
airplanes can yield important information on the health of crops and can help us see forest fires
even when they are enveloped in an opaque curtain of smoke.

The rainbow of colors we know as visible light is the portion of the electromagnetic spectrum
with wavelengths between 400 and 700 billionths of a meter (400 to 700 nanometers). It is the
part of the electromagnetic spectrum that we see, and coincides with the wavelength of greatest
intensity of sunlight. Visible waves have great utility for the remote sensing of vegetation and
for the identification of different objects by their visible colors.

Ultraviolet radiation has a range of wavelengths from 400 billionths of a meter to about 10
billionths of a meter. Sunlight contains ultraviolet waves which can burn your skin. Most of
these are blocked by ozone in the Earth's upper atmosphere. A small dose of ultraviolet radiation
is beneficial to humans, but larger doses cause skin cancer and cataracts. Ultraviolet wavelengths
are used extensively in astronomical observatories. Some remote sensing observations of the
Earth are also concerned with the measurement of ozone.

X-rays are high energy waves which have great penetrating power and are used extensively in
medical applications and in inspecting welds. X-ray images of our Sun can yield important clues
to solar flares and other changes on our Sun that can affect space weather. The wavelength range
is from about ten billionths of a meter to about 10 trillionths of a meter.

Gamma rays have wavelengths of less than about ten trillionths of a meter. They are more
penetrating than X-rays. Gamma rays are generated by radioactive atoms and in nuclear
explosions, and are used in many medical applications. Images of our universe taken in gamma
rays have yielded important information on the life and death of stars, and other violent
processes in the universe.

Despite their name, cosmic rays are not a part of the electromagnetic spectrum.
Instead of radiation, cosmic rays are high-energy charged particles that travel
through space at nearly the speed of light. Their extremely high energies are
comparable to those of gamma rays at the upper end of the electromagnetic
spectrum. The highest-energy cosmic rays originate outside our galaxy and
provide information on distant objects such as quasars. Cosmic rays are
detected when they hit the upper atmosphere, creating showers of particles in
their interaction with atoms. These secondary particles can then be detected by
instruments on the ground.