Waves transmittedA wave is passed across or through a material (medium), eg light waves are transmitted through air, glass and water. at the interface (boundary) between two materials may change direction. refractionProcess by which a wave changes speed and sometimes direction upon entering a denser or less dense medium, eg a light ray changes direction when refracted by a lens. is the change in direction of a wave at such a boundary. All wave types can be refracted.
It is important to be able to draw ray diagramDiagram that represents the direction and angle of travel of light. to show the refraction of a wave at a boundary.
Figure caption,
A ray diagram showing light wave refraction at the boundary between air and glass
Explaining refraction - Higher
The densityA measure of compactness and the ratio of mass to volume. It is usually measured in kilograms per metre cubed (kg/m3) or grams per centimetre cubed (g/cm3). of a material is one of the factors that affects the speed that a wave will be transmitted through it.