This animation has been
created to illustrate the phenomenon of wave refraction. Refraction of a
wave occurs when a wave passes from one medium to another in which it has
a different speed.
If a wave crosses a
boundary between two media 1 and
in which the wave speeds are v1
respectively, then the ratio
Snells law of refraction:
= sin θ1/sin θ2 = λ1/λ2
are the angles made by the waves and the normal to the boundary (the
dashed line in the animation) in media 1
respectively. The symbols
λ1 correspond to the
wavelength in the media 1 and 2 respectively.
This example shows that
by moving from a medium with high wave speed to a medium with low wave
speed, waves are refracted towards
the normal. When going from a medium with low wave speed to a medium with
high wave speed, it will be
refracted away from the normal as you can see by imagining this
animation running backwards.