3.14 understand that light waves are transverse waves which can be reflected, refracted and diffracted

Reflection
Light hitting a reflective surface will 'bounce' back from the surface (at the same angle they hit the surface.)

Refraction
Light waves change speed when they pass through objects of different densities, this causes them to change direction. When they return to the original density they will continue in the original direction.

Diffraction
When light meats a barrier, it will carry on through the gap and spread out in the area beyond.