Electromagnetic Spectrum

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Electromagnetic Spectrum

• Created by Dr. A. Davila

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In the above diagram the white line represents
the position of the medium when no wave is
present.
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Radio Waves

• Are produced by feeding an electric signal to the
  mast or antenna of a transmitter.

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Radio Waves

• Radio waves have the longest wavelengths in the
  electromagnetic spectrum.
• These waves can be longer than a football field
  or as short as a football.

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Radio Waves

• Radio waves have the longest wavelengths in the
  electromagnetic spectrum.
• These waves can be longer than a football field
  or as short as a football.

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Radio Waves

• The signal makes the electrons in the metal
  atoms of the mast or antenna change energy levels
  and emit light rays.

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RAYS TV reception uses radio_ waves The
SATELITE_ at Rays TV receives movies via radio
waves from a satellite TAXI_ - Car radio receives
radio wave signals TAXI_ - Driver receives
instructions on a CB radio which uses radio
waves. RADIO TOWER - broadcasts radio signals
LARGE SATELITE _ dish in field receives radio
waves from distant stars
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Microwaves

• Microwaves have wavelengths that can be measured
  in centimeters
• The longer microwaves, those closer to a foot in
  length, are the waves which heat our food in a
  microwave oven

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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Microwaves

• Microwaves are good for transmitting information
  from one place to another because microwave
  energy can penetrate haze, light rain and snow,
  clouds, and smoke.

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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Microwaves

• Shorter microwaves are used for radar like the
  doppler radar used in weather forecasts.
  Microwaves, used for radar, are just a few inches
  long.

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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MICROWAVES in Wavesgrill uses microwave to cook
food. Antennas on tower they send microwave
communications
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Infrared Waves

• The longer, far infrared wavelengths are about
  the size of a pin head and the shorter, near
  infrared ones are the size of cells, or are
  microscopic.

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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Infrared Waves

• The heat that we feel from sunlight, a fire, a
  radiator or a warm sidewalk is infrared.
• Shorter wavelengths are the ones used by your
  TV's remote control.

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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Infrared Waves

• Satellites like GOES 6 and Landsat 7 look at the
  Earth. Special sensors, like those aboard the
  Landsat 7 satellite, record data about the amount
  of infrared light reflected or emitted from the
  Earth's surface.

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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Infrared lights above food in Wavesgrill use
infrared waves to keep food hot Infrared remotes
- Remote controls use infrared waves to
communicate with the TV Trees, brashes, crops,
and short vegetation reflects short infrared
waves Astronomers study thermal infrared (long
infrared waves) from stars
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Visible Spectrum

• Cones in our eyes are receivers for these tiny
  visible light waves.
• The Sun is a natural source for visible light
  waves and our eyes see the reflection of this
  sunlight off the objects around us.

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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Visible Spectrum

• The color of an object that we see is the color
  of light reflected. All other colors are
  absorbed.
• Light bulbs are another source of visible light
  waves.

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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VISIBLE LIGHT Water droplets cause white light
to break apart into seven colors (Visible
Light). Portrait photographers use film
sensitive to visible light Astronomers look at
visible light from planets and stars
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Ultraviolet Waves

• Astronomers have to put ultraviolet telescopes on
  satellites to measure the ultraviolet light from
  stars and galaxies - and even closer things like
  the Sun

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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A tanning booth uses ultraviolet waves to tan our
skin ultraviolet waves - sunglasses protect our
eyes from the ultraviolet waves Sunblocks -
protects our skin from ultraviolet
waves ultraviolet waves astronomers see some
ultraviolet radiation from planets and stars
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X-Rays

• X-ray light tends to act more like a particle
  than a wave. X-ray detectors collect actual
  photons of X-ray light.
• The Earth's atmosphere is thick enough that
  virtually no X-rays are able to penetrate from
  outer space all the way to the Earth's surface.

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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X-Rays

• X-ray telescopes and detectors are placed on
  satellites. We cannot do X-ray astronomy from the
  ground can not be done from Earth
• comets emit X-rays
• The Sun also emits X-rays
• Many things in deep space give off X-rays

Images from http//science.hq.nasa.gov/kids/imag
ers/ems/gamma.html
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At EMS, Dr. Bob uses X-ray detectors collect
actual photons of X-ray light in his
Clinic. Nuclear Medicine is used to treat
cancer. Gamma radiation kills sick cells.
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Gamma Rays

• Gamma-rays are generated by radioactive atoms and
  in nuclear explosions
• They can kill living cells, a fact which medicine
  uses to its advantage, using gamma-rays to kill
  cancerous cells.

http//science.hq.nasa.gov/kids/imagers/ems/gamma.
html
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Gamma Rays

• .Gamma-rays travel to us across vast distances of
  the universe,
• Instruments aboard high-altitude balloons and
  satellites like the Compton Observatory provide
  our only view of the gamma-ray sky

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