Refraction

Medium=

The substance that the wave travel through

What is refraction

When a wave changes medium

What causes refraction

Refraction is caused by a change in the wave-speed (often due to a change in the density of the medium) which can cause a change in direction

What doesn’t change in refraction

Frequency

What is the angle of refraction

Angle between the normal line and the outgoing ray

What happens when a wave slows down

They bend towards the normal

What happens when a wave speeds up

They travel away from the normal

What happens if the wave enters or leaves the medium at a right angle

They do not change direction

What happens when the wavefronts start to move into the glass (or any other medium)

Those part of wavefronts slow down

This causes those parts of the wavefronts to get closer together and their wavelength gets smaller

This change in speed and wavelength causes the waves to change direction towards the normal

What happens if the wave enters a denser material

It bends towards the normal

What happens if the wave enters a less dense material

Bends away from normal