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Waves - refraction and Snell's law
This video models refraction using a vehicle travelling from a concrete surface to a grass surface and shows how the forward wheel slows and so the vehicle changes direction.
A diagram is then constructed to develop Snell’s law, i.e., the angle of incidence (from air) is proportional to the angle of refraction (through glass).
sinθi/sinθr = constant = n (refractive index).
The idea is further developed by stating that the refractive index is proportional to the speed at which the wave travels through the two mediums.
n = vi/vr
Although not given, this could be extended to show that:
vi/vr = sinθi/sinθr
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