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2013-03-25 21:30:54

description of science stuff
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    • author "me"
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    • Light
    • Energy u can see made of photons
  1. photons
    Tiny particles of light. Energy released by atoms through photons. Einstein won nobel prize for discoverin in 1921
  2. In the fifth century
    Empedocles said aphrodite made eye with fir in it.
  3. 1690
    Christian huygens agreed with davinci that light is wave. Pointed out when two beams cross they pass tgru eachother
  4. Huygens book was called
    Treatise on light
  5. 1862
    Scottish james maxwell discovered that waves travel at constant speed. He thought it was radiation. Supported huygens
  6. 1887
    German heinrich hertz discovered frequencies of light such as violet cause metals to lose electrons. Used red lught no effect. Showed. Violet light were stronger. Photoelectric effect. Agreed with newton
  7. Photoelectrif effect
    Movement of electrons when light shines on it
  8. Early twentieth century
    Einstein used previous works to explain photons. Photons energy level depended on light frequency
  9. Wave theory of light was accepted until...
    Einstein studied photoelectric effect. Indicated particle nature. Also as wave.
  10. Theory of wave particle duality
    Einstein created. States light is a wave and particle. Received nobel prize in 1922 for it
  11. Today
    Scientists think lught is a wave and particle. Particles in wave pattern
  12. Quantum mechanics
    Theoretical physics. Replaces classical mechanics at atomic and subatomic levels. From latin quantum means how many. Based on probability.
  13. Electromagnegic spectrum
    Range of electromagnetic waves in order. Transverse waves that transfer electric and magnetic energy. Travel at same speed. Different wavelengths and frequencies. Travel in vacuum. Electric and magnetic.
  14. Radiation in wavelengths u can see is
    Visible.light. mostly invisible
  15. Radiowaves
    Longest wavelength. Lowest frequency. Radio tv radar
  16. Microwaves
    Wireless and microwAves
  17. Infrared
    Energy as heat. Qll objects give off. Cant see,only feel. Shorter wavelengths and higher frequencies than microwaves
  18. Thermography
    Type of infrared. Thermographic cameras detect radiation and make images of it
  19. visible light
    Electromagnetic waves that are visible To human eye
  20. visible spectrum
    Composed of seven colors roy g biv . Form white. Newton discovered it. Coined term spectrum from Latin spectaculum or appearance
  21. Uv rays
    Frequencies hugher than visible light. More energy. Can damage or kill cells. Uv lamps used to kill hospital bacteria
  22. Xrays
    Higher grequencies than uv rays. Used in medicine
  23. Gamma rays
    Shortest wavelength and hughest frequency. Greatest energy. Given off in nucleur stuff
  24. Four properties of light are:
    Speed wavelength frequency and amplitude.
  25. Speed of light
    In a vacuum measured at 300000 km/s or 186000 m/s
  26. Wavelength
    Distance fro crest to trough of one wave to crest to tro of another
  27. Frequency
    Number of light wavs that pass by each second
  28. Amplitude
    Height of wave
  29. Luminous objects
    Give off own light
  30. Illuminated objects
    Can be seen bc they reflect light. Ex moon
  31. Opague
    Block light. Ex ur hand
  32. Transparent
    Allow light o pass thru unchanged. Ex clear glass water air
  33. Translucent
    Qllow some scattered light to pass thru. No details. Ex frosted glass and wax paper
  34. Reflection
    Bouncing back of wave when hits surface thru which it cant pass. Objects r seen bc light reflects off them
  35. Refraction
    Bending of light waves as enter other medium. When light enters new medium chabge in speed causes bending
  36. A lense
    Curved piece of glass used to refract light. Different shapes . New image based on shape