Light

• Brightness


  A person's perception of intensity
• Intensity


  Depends on the number of light waves passing through a square meter of space in one second
• the more waves that pass through


  Higher the intensity of the light wave
• Light's distance from source


  Affects intensity, like sound waves
• Light produced by stars

  • Less intense than light from the sun because the stars are farther from Earth
• Factors that affect brightness

  • Intensity
  • The light's distance from the source
  • One's sensitivity to light
• Electromagnetic Waves


  Measure in nanometers
• Electromagnetic Waves


  Travel at a much faster pace
• As the frequency of the wave increases


  The energy also increases
• Mechanical Waves (e.g. sound)

  • Use longitudinal wave
• Waves (both electromagnetic and mechanical)

  • Use transverse wave to demonstrate wave shape (mathematical)
• Light


  Does not require a medium to travel
• Types of wave interactions

  • Reflection
  • Absorption
  • Transmission
  • Refraction
• Transmission


  Occurs when light passes through matter
• Absorption


  Occurs when the energy of a wave is taken in by the new medium
• Reflection


  Occurs when a wave bounces off something that it is unable to go through
• Refraction


  The bending of light as it passes from one transparent substance into another at a different speed
• Colored objects reflect or absorb different wavelengths of light
• Absorbed light turns into thermal energy
• The human eye has two types of photoreceptors, rods (for dim light) and cones (for bright light).
• Cone cells can detect color and function best under bright lighting conditions.
• Cones detect color by responding differently to red, green, and blue light.
• The particle structure within the object determines


  Which wavelengths will be absorbed or reflected