Refraction and lenses

Science, Grade 10

1. Refraction and lenses
Telescopes use lenses and mirrors to collect and focus light from distant objects such as planets and stars. There are many types of telescopes that allow us to see into outer space. The simplest telescope, a refracting telescope, uses two lenses. The first lens, the objective, gathers and focuses the light. The second lens, the eyepiece, enlarges the image. A reflecting telescope includes a mirror to help gather light. Microscopes also use a combination of lenses to magnify objects. An objective lens and an eyepiece lens are used to magnify an object to produce a real and enlarged image. Optical fibers are long thin pieces of glass or plastic and are used to transmit light. Light travels along the fiber and only leaves at the other end. Optical fibers are used to send information between telephones or computers.