Or have you ever tried to light a piece of paper on fire by using a magnifying glass? Do you or any of your family members have glasses? All of these things use lenses - so do telescopes, binoculars, and microscopes. Your eyes themselves are lenses.

You learned that light rays will refract when they pass from one medium to another. When light rays pass from air into glass, they bend. A lens takes advantage of this tendency to refract or bend and puts it to use. Scientists and others use these curved pieces of glass called lenses to bend the light rays in a specific way.