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