The Electromagnetic Spectrum

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The Electromagnetic Spectrum

• By Christopher Wainwright Aaron Tom Baroni

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What is it?

• The electromagnetic spectrum is the complete
  spectrum or continuum of light including radio
  waves, infrared, visible light, ultraviolet
  light, X-rays and gamma rays
• An electromagnetic wave consists of electric and
  magnetic fields which vibrates thus making waves.

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The Electromagnetic Spectrum

• By Christopher Wainwright Aaron Tom Baroni

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Nature of Electromagnetic Waves

• They are Transverse waves without a medium. (They
  can travel through empty space)
• They travel as vibrations in electrical and
  magnetic fields.
• Have some magnetic and some electrical
  properties to them.
• Speed of electromagnetic waves 300,000,000
  meters/second (Takes light 8 minutes to move from
  the sun to earth 150 million miles at this
  speed.)

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• Waves or Particles
• Electromagnetic radiation has properties of waves
  but also can be thought of as a stream of
  particles.
• Example Light
• Light as a wave Light behaves as a transverse
  wave which we can filter using polarized lenses.
• Light as particles (photons)
• When directed at a substance light can knock
  electrons off of a substance (Photoelectric
  effect)

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Wavelength, Frequency and Energy

• Since all light travels at the same speed,
  wavelength and frequency have an indirect
  relationship.
• Light with a short wavelength will have a high
  frequency and light with a long wavelength will
  have a low frequency.
• Light with short wavelengths has high energy and
  long wavelength has low energy

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RADIO WAVES

• A. Have the longest wavelengths and lowest
  frequencies of all the electromagnetic waves.
• B. A radio picks up radio waves through an
  antenna and converts it to sound waves.
• C. Each radio station in an area broadcasts at a
  different frequency. on radio dial tells
  frequency.
• D. MRI (MAGNETIC RESONACE IMAGING)
• Uses Short wave radio waves with a magnet to
  create an image

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Bands of Radio/TV/Microwaves
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Microwaves

• Longer than radio, shorter than light and
  infrared
• Wavelength 1 x 10 - 4 m to 1 x 10-1 m
• First used in radar, now used in communication,
  medicine and consumer use (microwave ovens)

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Infrared waves

• Invisible electromagnetic waves that are detected
  as heat
• Can be detected with special devices such as
  night goggles
• Used in heat lamps
• Higher energy than microwaves but lower than
  visible light

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Visible Light

• The portion of the electromagnetic spectrum that
  human eyes can detect
• ROY G BIV (red, orange, yellow, green, blue,
  indigo, violet)
• Red is the lowest frequency and violet is the
  highest frequency

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Ultraviolet waves

• Higher energy than light waves
• Can cause skin cancer and blindness in humans
• Used in tanning beds and sterilizing equipment

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X-Rays

• High energy waves
• First discovered by Roentgen
• Used in medicine, industry and astronomy
• Can cause cancer

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GAMMA RAYS

• Shorter wavelength and higher frequency than
  X-rays
• Carry the greatest amount of energy and penetrate
  the most.
• Used in radiation treatment to kill cancer cells.
• Can be very harmful if not used correctly.

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Test Time

• 1. What is the relationship between frequency and
  wavelength?
• 2. What is meant by spectrum?
• 3. What does ROY G BIV mean?

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Now, lets really think

• 4. Can you actually see x-rays?
• Support your answer.
• 5. Which color is more energetic, red or yellow?
• 6. Which type of wave travels faster, gamma or
  radio?
• 7. Why are microwaves more dangerous than radio
  waves?

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Answers

• 1. Frequency and wavelength are properties of
  waves and since speed is constant for em waves,
  as frequency increases, wavelength decreases.
• 2. Spectrum is a continuum of all electromagnetic
  waves
• 3, ROY G BIV is the difference colors of the
  visible light in order of longest wavelength to
  shortest wavelength.
• 4. X-rays can not be seen, only the waves in the
  visible light portion are visible.
• 5. Yellow is higher energy than red because it
  has a shorter wavelength and higher frequency.
• 6. Both travel at the same speed, 300,000 km/s
  (all em waves travel at the same speed)
• 7. Microwaves have a higher frequency than radio
  and carry more energy.

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References

• en.wikipedia.org/wiki/Electromagnetic_spectrum
• imagine.gsfc.nasa.gov/docs/science/know.../emspect
  rum.html
• hyperphysics.phy-astr.gsu.edu
• science.hq.nasa.gov/kids/imagers/ems/ems.html

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The Electromagnetic spectrum

• By Anna Proctor Lindsey Ferris

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What the heck is the electromagnetic spectrum?!

• The Electromagnetic Spectrum is the range of all
  possible frequencies of electromagnetic
  radiation, or waves.
• It distributes or absorbs radiation through
  different objects.
• The full set of waves that can travel through
  space includes not only visible light but short
  waves.

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How colors are used to show the level of
frequencies.

• A special device is used to control the movement
  of electromagnetic waves. These waveguides are
  typically metal-based lines pitched at microwave
  frequencies to link connections between antennas
  and receivers. Its a one-way channel that picks
  up signals and an attenuator keeps the signals
  strength at a constant.

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Different types of radiation

• Radio waves are the longest wavelength in the
  electromagnetic spectrum.
• Infra red light is associated with heat and
  things that give off heat. Ex TV remote controls.

• Visible light is the only thing our eyes can
  detect in the Electromagnetic spectrum.
• Ultra-violet light is made by special lamps which
  in other words, replaces to sun. Ex tanning beds.

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More types of radiation

• Microwaves are transmitted through mobile phones.
• Gamma rays are the highest frequency waves

• X-rays are waves used to inspect luggage at an
  airport or to see through human skin to their
  bones.

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Measurements of the electromagnetic spectrum.

• The tiniest waves are measured in angstroms, a
  unit of length equal to one hundred-millionth of
  a centimeter.
• Waves of visible light are measured in
  nanometers (nm).
• While waves in infrared to radio are measured in
  more familiar meters.

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How else can wavelengths be measured?
The electromagnetic spectrum can be expressed in
terms of energy, wavelength, or frequency.
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Visible wavelengths!

• Are the only electromagnetic waves we can see. We
  see these waves as the colors of the rainbow.
  Each color has a different wavelength. Red has
  the longest wavelength and violet has the
  shortest wavelength. When all the waves are seen
  together, they make white light.

Each color of the rainbow corresponds to a
different wavelength of the electromagnetic
spectrum.
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This chart shows all the different colors and how
they are in relation to one another.

• 
  
  Color Charts

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A closer look at colors.

• This a picture at normal size, then blown up
  200, 400 and 800 times. Most pictures in magazine
  are made up of colored dots.
• A magazine printing press usually can only print
  four colors Cyan, Magenta, Yellow, and Black.
  Our eyes and brain put colors together from the
  colored dots.

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QUIZ TIMEEE.

• 
  
  QUIZ TIMEEE.

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Sources.

• http//www.learner.org/teacherslab/science/light/c
  olor/dots/index.html
• http//imagine.gsfc.nasa.gov/docs/science/know_l2/
  emspectrum.html
• http//science.hq.nasa.gov/kids/imagers/ems/ems.ht
  ml
• http//home.clara.net/darvill/emag/index.htm