Electromagnetic Waves

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Electromagnetic Waves

• Can travel through empty space (non-mechanical)
• Produced by charged particles in motion or by the
  decay of subatomic particles
• Travel as little bundles of energy called
  photons
• All travel at the speed of light in a vacuum
• c 300,000,000 meters/second (186,000
  miles/second)
• Have properties of both waves and particles

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Radio Waves

• Lowest Frequency and Energy on EM spectrum
• Largest Wavelength on EM spectrum
• AM radio (Amplitude Modulation)
• TV signals
• FM radio (Frequency Modulation)
• Aircraft communication
• Can be used to study outer space

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Microwaves

• Used for some communication (cell phone signals)
• Can penetrate clouds, haze, and weather
• Interacts with water molecules to heat food
• Theory suggests Spread throughout the universe
  from the Big Bang
• Used in RADAR -RAdio Detecting And Ranging
• Doppler RADAR uses microwaves to see moisture in
  the atmosphere

4
Infrared Waves

• TV remotes use infrared waves
• Carry heat energy
• Can be used in thermal imaging
• Night vision goggles
• Used by military and emergency responders
• Satellites can see temperature readings on earth
  from space

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Picture from space with infrared satellite
6
Visible Light

• EM radiation that can be detected by the human
  eye
• ROY G. BIV

7
Ultraviolet Waves

• Given off by the sun
• Harmful to humans- sunburn/ skin cancer/ eye
  damage
• UVA and UVB are both harmful
• Blacklights and tanning beds give off UV waves
• Absorbed by ozone in our atmosphere which
  protects us
• Can be used to purify water
• Can still penetrate clouds!

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X-rays

• Found by accident X-rays left marks on a screen
  that wasnt exposed to light
• X-rays penetrate flesh but get absorbed by
  calcium in bones
• They are created by high energy electrons
  changing orbitals.
• Large amounts are harmful to humans
• They are given off by the sun and other stars
• Most X-rays from space get absorbed by our
  atmosphere
• Can be used in other types of imaging to see
  inside the body

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Gamma Rays

• Highest energy and frequency on EM spectrum
• Shortest wavelength on EM spectrum
• Given off as a bi-product of nuclear decay and
  radioactive atoms
• Able to kill living cells- good and bad
• Can be used to fight certain types of cancer and
  prevent artery blockages
• Like x-rays, they get absorbed by our atmosphere