In this subunit it is assumed that students have no prior formal knowledge of the subject beyond their existing own conceptions. The activities introduce students to the following ideas and concepts:

  • Objects may be classified by their optical characteristics
  • Light has physical properties such as colour and intensity
  • Shadows are caused by the absence of light
  • Light may not necessarily be visible to the naked eye
  • Light is emitted as a wave
  • The direction of propagation of these waves may be represented as rays
  • Mirrors reflect light and, for a plane mirror, the angle of incidence is equal to the angle of reflection
  • The direction of light can change as it passes from one medium to another
  • White light is the combination of lots of different colours of light
  • White light can be produced using just red, green, and blue primary colours
  • Filters pass certain colours of light and absorb others
  • Lenses alter the direction of light and can be used to form images