Why mirror reflects light
Why mirror reflects light
What happens when you look in a mirror? In the daytime, light reflects off your body in all directions. That's why you can see yourself and other people can see you. Your skin and the clothes you're wearing reflect light in a diffuse way: light rays bounce off randomly, haphazardly, in no particular direction. Stand in front of a mirror and some of this light from your body will stream in straight lines toward it. Rays of light (which are really packets of light energy called photons, fired in a stream like bullets from a machine gun) shoot through the glass and hit the silveroating behind it (possibly a real coating of silver or more likely something less expensive such as polished alumnium). The light will reflect off the mirror in a more orderly way than it reflects off your clothes. We call that specular reflection—it's the opposite to diffuse reflection.
How does the mirror reflect light? The silver atoms behind the glass absorb the photons of incoming light energy and become excited. But that makes them unstable, so they try to become stable again by getting rid of the extra energy—and they do that by giving off some more photons. (You can read about how atoms take in and give out photons in our article about light.) The back of a mirror is usually covered with some sort of darkly colored, protective material to stop the silver coating from getting scratched, and also to reduce the risk of any light seeping through from behind. Silver reflects light better than almost anything else and that's because it gives off almost as many photons of light as fall on it in the first place. The photons that come out of the mirror are pretty much the same as the ones that go into it
What happens when you look in a mirror? In the daytime, light reflects off your body in all directions. That's why you can see yourself and other people can see you. Your skin and the clothes you're wearing reflect light in a diffuse way: light rays bounce off randomly, haphazardly, in no particular direction. Stand in front of a mirror and some of this light from your body will stream in straight lines toward it. Rays of light (which are really packets of light energy called photons, fired in a stream like bullets from a machine gun) shoot through the glass and hit the silveroating behind it (possibly a real coating of silver or more likely something less expensive such as polished alumnium). The light will reflect off the mirror in a more orderly way than it reflects off your clothes. We call that specular reflection—it's the opposite to diffuse reflection.
How does the mirror reflect light? The silver atoms behind the glass absorb the photons of incoming light energy and become excited. But that makes them unstable, so they try to become stable again by getting rid of the extra energy—and they do that by giving off some more photons. (You can read about how atoms take in and give out photons in our article about light.) The back of a mirror is usually covered with some sort of darkly colored, protective material to stop the silver coating from getting scratched, and also to reduce the risk of any light seeping through from behind. Silver reflects light better than almost anything else and that's because it gives off almost as many photons of light as fall on it in the first place. The photons that come out of the mirror are pretty much the same as the ones that go into it
