wave properties

Reflection

angle of incidence = angle of reflection

the line in the middle is the normal

Refraction

Refraction is the change of direction of waves when they travel across a boundry

From air to glass angle of refraction < angle of incidence

From glass to air angle of refraction > angle of incidence

Diffraction

Diffraction is thespreading out of waves, passing through gap or around something

The narrower the gap, greater the diffraction