How Light Bounces> I love to watch waves crash on a beach. Especially a rocky beach. Picture it: A wave of water hits the rocks. Some of the water soaks into the rocks and stays there. But a lot of water bounces off the rocks. If the rocks are chunky and rough, watch out! The water sprays all over the place, every which way.
Light rays are a bit like ocean waves. They crash into objects, especially objects that are opaque (not see-through). Some light rays are absorbed. They soak into the object. But many rays <#5643,5118><!reflect>, or bounce off, the object. A rough object such as a brick wall makes the rays bounce all over, every which way. A smooth object, like a mirror, causes the rays to bounce in an orderly way. They hit a mirror and bounce off at the exact same angle.
Here’s another way to picture it: Imagine dropping balls onto a flat floor. The balls mostly bounce straight back up. Now imagine dropping the balls on a rougher surface, such as gravel. The balls scatter. They bounce up at different, and not always predictable, angles. The rougher the surface, the more the balls scatter. Rough surfaces make light rays scatter too. Even a piece of paper scatters light in all directions.
Reflected light is all around you. Light reflects off a piece of paper, off walls, and even off the moon! Moonlight is really just sunlight that hits the moon and bounces off.
Some surfaces, such as mirrors, can be curved. A surface that curves in on itself, like the inside of a bowl, is called <#5644,5116><!concave> (think “caved in”). Surfaces which curve outwards, like the outside of a bowl, are called <#5645,5117><!convex>. You can use my Laser Lab to see for yourself how using the flat and curved mirrors affect the way light bounces.
