Reflection

light · waves · physics · bounce

Mirrors use reflection. When light hits a mirror, it bounces straight back at the same angle it came in. This is why you can see yourself in a mirror, perfect and clear.

Water waves bounce too. Ocean waves don't just disappear when they hit a wall or cliff. They bounce back out to sea, following the same angle rule that light does.

Sound bounces everywhere. When you shout in a canyon or empty room, you hear an echo because sound waves bounce off hard surfaces and come back to your ears.

The angle rule always works. Scientists call it the law of reflection: the angle going in equals the angle going out. It works for light, sound, water, and almost any wave you can think of.

Shiny vs. rough surfaces. Smooth, shiny surfaces like mirrors reflect waves perfectly, but bumpy surfaces scatter the waves in many directions instead.