Copyright © 2007 Dorling Kindersley
Reflections are usually caused by shiny things, such as MIRRORS, that show a reversed image of whatever is placed in front of them. The image seems to be as far behind the mirror as the object is in front of it. Not only mirrors make reflections, however. Most objects reflect some of the light that falls on them. In daytime we see familiar objects like grass, trees, and the sky only because they reflect light from the Sun into our eyes.
A rough surface, such as this rippling pond, causes light rays to bounce off it in many different directions. It may still be possible to make out an image on the surface, or, if it is very rough, the image is very broken up. Most objects reflect light in this irregular way. Although we can see them, we cannot see any images reflected in their surfaces.
A mirror is a very smooth, highly polished piece of metal or plastic that reflects virtually all the light that falls onto it. The reflection appears to be behind the mirror and may look bigger, smaller, or the same size as the thing it is reflecting, depending on the mirror’s shape. We use mirrors when checking our appearance or driving. They also play an important part in telescopes, microscopes, cameras, and other optical (light-based) instruments.
A concave mirror curves or bends inwards and makes an object look bigger and nearer than it actually is. It works by making light rays seem to come from a point in front of the mirror, which is closer to our eyes. Concave mirrors are important in such things as bicycle reflectors and reflecting telescopes.
Drivers use mirrors to see traffic coming up behind them. It is important for drivers to see as much of the road behind as they can, so wing mirrors and rear-view mirrors are convex. A drawback is that they make vehicles on the road behind look smaller and further away than they would in a flat mirror of the same size. Drivers must remember that the vehicles are nearer than they appear.