Pre-lab PowerPoint Lesson for S.W.A.T. E-lab

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• Pre-lab PowerPoint Lesson for S.W.A.T. E-lab

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It all starts with vibrations!

• Vibrations are waves of energy that move from one
  place to another.
• These vibrations can occur in.
• Water waves on the ocean shore
• Electricity running through a wire
• Light from the Sun or light bulbs
• Air vibrating string in a piano

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Electromagnetic Spectrum

• Whenever you watch TV, send a text message, or
  heat food in a microwave, you are using waves.
  Some waves, like sound waves, need molecules to
  travel through. This is why you can hear sound
  in our atmosphere but not in space.
• Some waves, however, do not need molecules to
  travel. These waves are called electromagnetic
  waves. These waves can travel through solid
  materials - but they can also travel through
  empty space.

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Electromagnetic Waves

• The word electromagnetic comes from the two words
  electricity and magnetism. When an electric
  field and magnetic field move together, they make
  waves - electromagnetic waves!

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Parts of Waves

• Waves go up and down, and they move forward -
  like a shaken rope.

(How Long)
(How Tall)
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Wavelength

• The length of a wave from crest to crest is
  called WAVELENGTH. The different waves of the
  spectrum can be as small as the nucleus of an
  atom, or as big as a planet!

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Frequency

• How many waves move pass a point in one second is
  called FREQUENCY. The more wiggles the higher
  the energy.

Different colors of light are due to waves of
different length and frequency
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Amplitude

• The height of a wave is referred to as AMPLITUDE.

With sound waves, the higher the amplitude, the
louder the noise.
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Types of Waves

• There are many types of waves along the
  electromagnetic spectrum, from very long radio
  waves to very short gamma rays. We are only able
  to see a small portion of this spectrum called
  visible light. However, scientific instruments
  use the full range of the electromagnetic
  spectrum to study and learn about both Earth and
  space.

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Radio Waves

• Radio waves have the longest wavelengths in the
  electromagnetic spectrum. They can be as large as
  a football field to larger than our planet! They
  have the lowest frequency of all the
  electromagnetic waves. Since radio waves can
  carry energy, we use them to transmit information
  by changing either the frequency or the amplitude
  of the radio wave to encode a message.
• Radio waves are useful because they can travel
  through many different materials, like clouds,
  without being absorbed.
• Radio telescopes are used to view planets,
  comets, giant clouds of gas and dust, stars, and
  galaxies.

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Microwaves

• Microwaves are higher frequency than radio waves.
  They range in size from about 1 millimeter to 1
  foot long. You are probably most familiar with
  them when you heat your food up in a microwave,
  but they have a lot more uses including weather
  forecasting and cell phones! Microwaves can even
  pass through clouds, which make them an excellent
  wavelength for transmitting satellite
  communications.
• In 1965, two scientists at Bell Labs, Arno
  Penzias and Robert Wilson, detected a strange
  background noise. The scientists soon realized
  that they had discovered noise left over from the
  Big Bang that began the universe billions of
  years ago!

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Infrared

• Infrared waves are about the length of a grain of
  sand. While we cannot see infrared, we can sense
  some of the energy as heat.
• Infrared light is used in television remote
  controls and even in video games. We can use
  infrared cameras to study heat loss patterns,
  such as from a house. This can help us to better
  insulate openings such as doors and windows to
  keep thermal energy in and reduce the cost to
  heat the house.
• Infrared energy can reveal objects in the
  universe that cannot be seen in visible light
  using optical telescopes. Infrared light is
  helpful in studying new stars because often dense
  gas clouds block their visible light.

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Visible Light

• All electromagnetic radiation is light, but we
  can only see a small portion of this radiation.
  This is the part of the spectrum we call visible
  light.
• Each color of the visible light spectrum has a
  different wavelength. This is why when white
  light travels through a prism, the wavelengths
  separate into the colors of the rainbow.
• Your color TV has only red, green and blue dots
  but these make all the other colors on your
  screen. Objects appear to be different colors
  because they absorb different amounts of the red,
  green and blue light. They reflect the rest of
  the wavelengths in visible light and this is the
  color we see.

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Radiation from Sun

• About 43 of the total radiant energy from the
  sun is in the visible parts of the spectrum.
• Most of the remainder is in the near-infrared
  (49) and ultraviolet section (7).
• Less than 1 of solar radiation is emitted as
  x-rays, gamma waves, and radio waves.

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Ultraviolet

• Ultraviolet (UV) light has shorter wavelengths
  than visible light. Although UV waves are
  invisible to the human eye, some animals can see
  them.
• The Sun is a source of the full spectrum of
  ultraviolet radiation, UV-A, UV-B, and UV-C
  waves. UV-C rays are the most harmful but are
  almost completely absorbed by our atmosphere.
  UV-B rays are the harmful rays that can cause our
  skin to burn. About 95 percent of UV-B rays are
  absorbed by ozone in the Earth's atmosphere.
• Young stars shine most of their light in the
  ultraviolet wavelength, so scientists are able to
  study the formation of new stars using
  ultraviolet telescopes.

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X-Rays

• X-rays have much higher energy and much shorter
  wavelengths than ultraviolet light.
• X-rays were first studied in 1895 by a German
  scientist named Wilhelm Conrad Roentgen. He
  discovered that aiming x-rays through the human
  body created detailed images of the bones inside.
  Because bones are so dense, they absorb more
  x-rays than skin does creating shadows on the
  x-ray film.
• Some things in space naturally emit x-rays. The
  hotter the object is, the shorter the wavelengths
  that are emitted.
• Earth's atmosphere blocks x-ray radiation. This
  is beneficial for us here on Earth, because
  x-rays are so energetic that they would harm
  almost every living thing on earth!

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Gamma Rays

• Gamma rays have the smallest wavelengths and the
  most energy of all the waves. They are produced
  by the hottest and most energetic objects in the
  universe.
• On Earth, gamma waves are created by nuclear
  explosions, lightning, and radioactive decay.
• Exposure to these high-energy waves can cause
  damage to cells in living things. Sometimes,
  though, these changes to cells can be helpful.
  Gamma radiation is used to kill cancer cells.
• Gamma-ray bursts are the most energetic and
  luminous electromagnetic events and can release
  more energy in 10 seconds than our Sun will emit
  in its entire 10-billion-year expected lifetime!
  Scientists can also use gamma rays to determine
  the elements on other planets.

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Dangers of the Spectrum

• Some waves can be harmful if you are exposed to
  them for too long. The side of the spectrum with
  wavelengths shorter than visible light tend to be
  more dangerous to humans because they can have
  effects on the cellular level.
• The Sun bombards our Earth constantly with
  electromagnetic energy. However, the Earth's
  atmosphere protects us from higher energy waves
  that can be harmful to life.
• Some waves, such as visible light and microwaves,
  pass through the atmosphere. While the atmosphere
  is essential to protecting life on Earth, it is
  not helpful when it comes to studying waves in
  space. Because it blocks much of the radiation,
  instruments have to be positioned above the
  atmosphere in order to study higher energy and
  even some lower energy sources.

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Now lets see you create your own electromagnetic
spectrum in the Spectrum Scramble Activity!