Reflection, Refraction, and Diffraction

Reflection occurs when waves bounce off an object at the same angle that they hit it from.

Source: http://www.physicsclassroom.com/Class/waves/u10l3b.cfm

Refraction occurs when a wave bends, causing a change in speed.

Source: http://www.physicsclassroom.com/Class/waves/u10l3b.cfm

Dfifraction occurs when a wave bends around a barrier.

Source: http://www.physicsclassroom.com/Class/waves/u10l3b.cfm