In this activity, students investigate specular and diffuse reflection1 by looking into a dark box and shining a torch at various objects, coloured paper and a mirror.
By the end of this activity, students should be able to:
- describe how objects can only be seen if there is a light source
- explain that diffuse2 reflection3 is when light reflects off a rough surface and travels in all different directions
- explain that specular reflection4 is when light reflects off a mirror or other shiny surface and that the angle of reflection5 is always the same as the angle of incidence
- describe how different coloured objects only reflect certain colours of light
- describe how different colours of reflected light can combine to produce new colours.
Download the Word file (see link below) for:
- introduction/background notes
- what you need
- what to do
- discussion questions
- student handout.
- diffuse reflection: The reflection of light from a rough surface in which the incident light rays are reflected from the surface at many different angles.
- diffuse: Spread out.
- reflection: 1. The change in direction, or bouncing back of a wave when it strikes a surface. 2. Mirroring. 3. Casting back, as in light or heat.
- specular reflection: The reflection of light from a smooth surface in which the incident light rays are reflected from the surface such that the angle of reflection equals the angle of incidence.
- angle of reflection: The angle between the reflected ray moving away from a flat surface and an imaginary line (called the normal) perpendicular to the surface at the point of reflection.