LIGHT

• transparent


  (adj.) allowing light to pass through; easily recognized or understood; easily seen through or detected (window glass)
• translucent


  allows light to pass through but scatters the light so no image can be seen (tracing paper)
• opaque


  not letting light through (wood, cardboard)
• reflection


  angle of incident = angle of reflection (periscope)

  
• refraction


  The bending of a wave as it passes at an angle from one medium to another

  
• characteristics of the pinhole camera


  - the image in a pinhole camera is inverted and laterally reversed

  
  

  -as the camera is moved closer to the object, the image gets larger

  
  

  - making the pinhole larger makes the image brighter and fuzzier

  
  

  - making three holes, gives three images

  
  

  - to have a bright and sharp image, we need a large aperture and a lens
• similarities between the eye and the camera


  both use a lens to focus on the image

  
  

  both have a light, sensitive material to capture the image

  
  

  both have an aperture (hole) to control the amount of light entering
• differences between the eye and the camera

  a camera moves the lens backwards and forwards to focus the image but in the eye the lens change shape

  
  

  a camera has a shutter to control how much light falls on the film/sensor but the eye dooesn't
• eye diagram

  
• iris -

  lens -

  cornea -

  retina -

  the coloured part of the eye that controls the amount of light entering

  the part of the eye that changes its shape to focus light

  a convex transparent window that does most of the eye focusing

  the cells here are photosensitive. an image formed on the eye's retina will be upside down
• white light


  made up of the seven colours of the prism:

  red, orange, yellow, green, blue, indigo, violet

  
  

  when light goes into a prism, each colour is slowed down by a slightly different number

  
• what do we call the seperation of white light and how is it done?

  dispersion - pass white light through a prism
• which is refracted most, red/violet

  violet
• how can white light be named again


  pass the spectrum through a second, inverted prism
• is black a colour

  no, it is the absence of light
• what are the primary and secondary colours


  primary - red, blue, green

  secondary - magenta, yellow, cyan

  
• where would you find the three secondary colours used to reproduce all colours

  in a printer
• what is a filter?


  absorbs some colours of white light and lets other colours through to create coloured light
• what would a red filter result in?

  
• what would a magenta filter result in?