Can we turn back time? Ask a savvy physicist, and the answer will be “it depends.” Schemes for retrograde time travel abound but usually involve irreconcilable paradoxes and rely on outlandish ...

Waves close wavesVibrations that transfer energy from place to place without the transference of matter. - including sound and light - can be reflected at the boundary between two different materials.

Understand the physics behind total internal reflection and why light can become completely trapped inside a medium. This video explains the conditions required for total internal reflection, the role ...