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The Electromagnetic Spectrum http://amazing-space.stsci.edu/resources/explorations/groundup/lesson/basics/index.php?return=true

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The electromagnetic spectrum is the entire range of energy carried by electromagnetic waves. a. ... The longest electromagnetic waves are called radio waves. c. – PowerPoint PPT presentation

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Title: The Electromagnetic Spectrum http://amazing-space.stsci.edu/resources/explorations/groundup/lesson/basics/index.php?return=true


1
The Electromagnetic Spectrumhttp//amazing-space.
stsci.edu/resources/explorations/groundup/lesson/b
asics/index.php?returntrue
2
Electromagnetic Waves
  • 1. Stars send energy called electromagnetic waves
    into space.
  • a. Unlike other types of waves, electromagnetic
    waves travel through empty space.
  • b. The kind of energy that electromagnetic waves
    carry is called radiant energy.
  • 2. The electromagnetic spectrum is the entire
    range of energy carried by electromagnetic waves.
  • a. The shortest electromagnetic waves are called
    gamma rays.
  • b. The longest electromagnetic waves are called
    radio waves.
  • c. Humans can directly observe a small part of
    the electromagnetic spectrum, which is called
    visible light.

3
  • 3. The amounts of different types of radiant
    energy stars emit vary from star to star,
    depending on the temperature of the star.
  • a. Hot stars emit most of their radiant energy as
    short electromagnetic waves, such as gamma rays
    and X-rays. These waves have higher energy.
  • b. Cool stars emit most of their radiant energy
    as long electromagnetic waves with low energy,
    such as radio waves and infrared waves.

4
  • 4. Planets and moons do not emit their own light.
    Instead, they reflect light from the Sun. That is
    the reason we can see these objects in the sky.
  • 5. All light waves travel at 300,000 km/s, which
    is called the speed of light.

5
What is the electromagnetic spectrum?
  • The electromagnetic spectrum consists of all the
    different wavelengths of light (also known as
    electromagnetic radiation), including visible
    light, radio waves, and X-rays.
  • Light is a continuum of wavelengths. We name
    regions of the spectrum a bit arbitrarily, but
    the names give us a general sense of the energy
    for example, infrared light has shorter
    wavelengths than radio light. The only region in
    the entire electromagnetic spectrum that our eyes
    are sensitive to is the visible region.
  • http//www.youtube.com/watch?vlwfJPc-rSXwlistPL
    09E558656CA5DF76index1

6
Wavelength and frequency
  • Light is measured by its wavelength (in
    nanometers) or frequency (in Hertz).
  • One wavelength equals the distance between two
    successive wave crests or troughs.
  • Nanometer - A very small fraction of a meter.
    There are a billion (1,000,000,000) nanometers
    (nm) in one meter
  • Frequency (Hertz) equals the number of waves that
    passes a given point per second.

7
Wavelength, Frequency and Energy
  • Short wavelength high frequency high energy
  • Long wave length low frequency low energy

8
Gamma rays
  • Gamma rays have the shortest wavelengths, lt 0.001
    nanometers (about the size of an atomic nucleus).
  • This is the most energetic region of the
    electromagnetic spectrum.
  • Gamma rays can result from high-energy reactions
    taking place in objects such as pulsars, quasars,
    and black holes.
  • http//www.youtube.com/watch?vTA5SLDiIUWslistPL
    09E558656CA5DF76

9
X-rays
  • X-rays range in wavelength from 0.00110
    nanometers (about the size of an atom).
  • They are generated, by superheated gas from
    exploding stars and quasars, where temperatures
    can reach more than 10 million degrees Celsius.
  • http//www.youtube.com/watch?vCCAYcuCWOnMlistPL
    09E558656CA5DF76

10
Ultraviolet Radiation
  • Ultraviolet radiation has wavelengths of 10400
    nanometers (about the size of a virus).
  • Young, hot stars produce a lot of ultraviolet
    light that bathes interstellar space with this
    energy and causes nearby gas to glow as nebulae.
  • http//www.youtube.com/watch?vQW5zeVy8aE0listPL
    09E558656CA5DF76

11
Visible light
  • Visible light covers the range of wavelengths
    from 400700 nanometers (from the size of a
    molecule to a protozoan).
  • Our Sun emits most of its radiation in the
    visible range, which our eyes perceive as the
    colors of a rainbow. Our eyes are sensitive only
    to this small portion of the electromagnetic
    spectrum.
  • ROY G BIV

Red Orange Yellow Green Blue Indigo Violet
http//www.youtube.com/watch?vPMtC34pzKGclistPL
09E558656CA5DF76
12
Infrared wavelengths
  • Infrared wavelengths span from 700 nanometers 1
    millimeter (from the width of a pinpoint to the
    size of small plant seeds).
  • Infrared radiation is associated with heat. At a
    temperature of 98.6 degrees Fahrenheit (37
    degrees Celsius) , our bodies radiate with a peak
    intensity near 900 nanometers.
  • http//www.youtube.com/watch?vi8caGm9Fmh0listPL
    09E558656CA5DF76

13
Microwaves
  • Microwaves have wavelengths between 1 millimeter
    and 1 meter.
  • The radiation resulting from the "big bang" is
    detected in the microwave region and is often
    referred to as the microwave background
    radiation.
  • Microwave ovens use a specific microwave
    frequency to cause water molecules to absorb the
    energy and thus heat food.
  • http//www.youtube.com/watch?vUZeBzTI5OmklistPL
    09E558656CA5DF76

14
Radio Waves
  • Radio waves are longer than 1 meter. Because
    these are the longest waves, they have the lowest
    energy and are associated with the lowest
    temperatures.
  • Radio wavelengths are found many places in a
    variety of stars (especially binary, X-ray, and
    other active stars), in interstellar clouds, in
    pulsars, and in the cool remnants of supernova
    explosions.
  • Radio stations use radio wavelengths to send
    signals that our radios then translate into
    sound.
  • http//www.youtube.com/watch?vOzDmEA8x0nQlistPL
    09E558656CA5DF76

15
EMS SONG
  • www.youtube.com/watch?v5UK5_P2bW9g
  • Whole EMS video
  • http//www.youtube.com/watch?vpYE8UHcL_gU
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