Electromagnetic spectrum
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Electromagnetic spectrum






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Electromagnetic spectrum Electromagnetic spectrum Presentation Transcript

  • Waves of the Electromagnetic Spectrum Blue - Highlight it
  • 1. Wave Properties
    • Crest: the highest point of a wave.
    • Trough: the lowest point of a wave.
    • Rest Line (Equilibrium): the mid-point position of the wave (the dotted line).
  • 1. Wave Properties
    • D. Amplitude: a measure of how high the crest is (or how low the trough is); measured from the rest line.
    • 1. The greater the amplitude, the more energy a wave carries.
  • 1. Wave Properties
    • E. Wavelength: the distance from one point on a wave to the corresponding point on the next wave.
  • 1. Wave Properties
    • F. Frequency: number of wavelengths passing a given point per second.
    • Longer wavelengths equal smaller frequencies .
    • Shorter wavelengths equal larger frequencies .
  • 2. Mechanical Waves A. use matter to transfer energy; travel faster when atoms are closer together
    • B. Transverse wave: wave energy causes matter in the medium to move up and down OR back and forth at right angles (perpendicular) to the wave.
    • C. Compressional wave: Matter in the medium moves forward and backward in the same direction as the wave.
      • Sound waves.
      • AKA Longitudinal Waves.
  • 3. Electromagnetic Waves
    • Can transfer energy WITHOUT using matter.
    • Produced by electrically charged particles.
    • C. Travel faster when fewer atoms are present:
      • Vacuum: 300,000 km/s
      • Air: slightly less than 300,000 km/s
      • Water: 226,000 km/s
      • Glass: 200,000 km/s
      • Diamond: 124,000 km/s
  • 4. Radio Waves A. Low-frequency electromagnetic waves with wavelengths from less than 1 cm to about 1,000 m.
    • 1. RADAR: RAdio Detecting And Ranging
      • By measuring the time required for radio waves to bounce off an object and return to the receiver, speed and location of the object can be found.
      • Used by law enforcement and air traffic controllers.
    • 2. MRI: Magnetic Resonance Imaging
      • Radio wave energy causes protons in the body to react and release energy.
      • The energy is detected by a receiver that maps the tissues and creates a picture of the inside of the body.
  • 5. Radio Waves in Space
    • Objects in space such as stars, galaxies, and nebulae emit electromagnetic radiation in the form of radio waves.
    • Radio astronomers use large radio telescopes to collect the radio waves and study the data collected.
    Image of Carbon Monoxide gas (CO) in the Milky Way Galaxy.
  • 6. Visible Light
    • The range of electromagnetic waves that you can detect with your eyes.
    • Length varies from 390 billionths to 770 billionths of a meter.
    • The color we see is the one being reflected .
    • Red has the longest wavelength.
    • Violet has the shortest.
    • When all colors are being reflected , we see white .
    • When all colors are being absorbed , we see black .
  • 7. Visible Light in Space
    • Satellite data is used to create true-color and false-color images of objects in space.
      • True-color : created using red, green, and blue light waves that are reflected off the surface.
      • False-color : created from data collected about the brightness of the light waves that are being reflected.
    True color False Color Planet Uranus
  • 8. Microwaves
    • Microwaves range from 1 meter to 1 millimeter and therefore overlap the Radio wave band.
    • Microwaves are good for transmitting information.
      • they can penetrate haze, light rain and snow, clouds, and smoke.
    • C. Scientists use microwaves to look for evidence of how the universe began.
      • In the 1960's scientists discovered cosmic microwave background radiation.
      • This radiation, which fills the entire Universe, is believed to be a clue to its beginning, something known as the Big Bang.
  • 9. Infrared Waves
    • Infrared light lies between the visible and microwave portions of the spectrum.
      • Longer waves are about the size of a pin head.
        • thermal
      • shorter ones are the size of cells, or are microscopic.
        • TV remote controls
    • B. Infrared radiation is great for studying cloud structure.
      • Shows more cloud detail than standard pictures.
    • C. Satellites have instruments that measure and record infrared radiation.
  • 10. Ultraviolet Waves (UV)
    • UV waves are shorter than visible light; therefore, have a higher frequency.
      • Not visible to the human eye.
    • Have enough energy to enter skin cells and cause cell damage, even cancer.
      • Earth’s atmosphere (ozone layer) blocks most, but not all UV.
    • Useful in killing bacteria.
    • Can make some material fluoresce; used by Police to find seemingly hidden evidence.
  • 11. X-Rays
    • X-rays have smaller wavelengths and therefore higher energy.
      • X-ray light tends to act more like a particle than a wave. They either pass through or are absorbed by the materials.
    • Black holes, neutron stars, binary star systems, and supernova remnants all emit X-rays.
      • X-Rays are blocked by the atmosphere & must be studied from space.
  • 12. Gamma Rays
    • Gamma-rays have the smallest wavelengths and the most energy of any other wave in the electromagnetic spectrum.
      • Waves are generated by radioactive atoms and in nuclear explosions.
    • Gamma-rays are produced by:
      • violent events such as supernova explosions
      • less dramatic events, such as the decay of radioactive material in space.
  • Electromagnetic Spectrum