5-WAC-01 Using a Raybox / Ray Diagrams

Outcomes

• Pupils can use a raybox.
• Pupils can construct ray diagrams.

Specification References

• 3.16 construct ray diagrams to illustrate the formation of a virtual image in a plane mirror

Starter

• Give pupils one minute to list words they associate with light.

Main Body of Lesson

• Demonstrate to pupils how a raybox works.
  • It is now standard to tape down a piece of A3 paper to the bench before using a raybox.
• Have pupils (in pairs) set up a raybox. Walk around the room with semicircular prisms and issue prisms to those pupils who have correctly set up their raybox.
• Ask pupils to "experiment" with the prisms and the rayboxes, to see if they can create any interesting effects. Have them demonstrate these effects to you.
• Collect in prisms but not rayboxes.
• Demonstrate the key features of ray diagrams and reference the similarities/parallels with the rayboxes.
  • Rays of light are always straight lines.
  • Rays of light begin at something.
  • Rays of light have arrowheads to show their direction (you might want to point out here that diagrams wouldn't change if direction reversed therefore the reflection interaction is symmetric with respect to time.)
  • The normal is an imaginary line drawn at right angles to a surface.
• Have pupils practice drawing the normal to a surface, using protractors (WRKXXX).

Plenary

• Next week on 5-WAC: The Law of Reflection

Additional Information

Resources Required

• Demonstration raybox
• Class set of rayboxes
• Perspex blocks - semicircular prisms only.
• A3 paper
• Protractors