5-WAC-03 Refraction / Reflection
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Contents
Outcomes
- Pupils understand that light travels at different speeds in different media.
- Pupils understand that the changing speed of light leads to the pheonmenon of refraction.
Specification References
- 3.14 recall that light waves are transverse waves which can be reflected, refracted and diffracted
- Diffraction is SA only
- 3.17 describe experiments to investigate the refraction of light, using rectangular blocks, semicircular blocks and triangular prisms
- 3.18 recall and use the relationship between refractive index, angle of incidence and angle of refraction
- 3.19 describe an experiment to determine the refractive index of glass, using a glass block
- 3.21 recall the meaning of critical angle c
Starter
- Ask pupils to estimate their top speeds on land and in water.
- Land: 10m/s (100m runner); water: 2.4m/s (50m swimmer)
Main Body of Lesson
- Show pupils the Trigonometry Triangle
- Have pupils plot a sine curve on graph paper, from 0 to 360 degrees every 30 degrees.
- Talk about the relationship between angle and sine(angle) and about inverse sine by "reading across" from the graph and down to angles.