How does it work Powerful microscopes shed new light on the teeny tiny and make the invisible, visible. They've played an enormous part in science by taking us deep into worlds we've come to think of as "microscopic." Besides, microscopes are effectively just tubes packed with lenses, curved pieces of glass that bend light rays passing through them. The simplest microscope of all is a magnifying glass made from a single convex lens, which typically magnifies by about 5–10 times. Microscopes used in homes, schools, and professional laboratories are actually compound microscopes and use at least two lenses to produce a magnified image. There's a lens above the object (called the objective lens) and another lens near your eye (called the eyepiece or ocular lens). Each of these may, in fact, be made up of a series of different lenses. Most compound microscopes can magnify by 10, 20, 40, or 100 times, though professional ones can magnify by 1000 times or more. For greater magnification than this, scientists generally use electron microscopes. To see a fly's eye in detail, our own eyes would need to be able to process details that are millimeters divided into thousands—millionths of a meter (or microns, as they're usually called). To study a fly's eye really well, we need it to be maybe 10–100 cm (4–40 in) across: the sort of size it would be in a nice big photo. That's the job a microscope does. Using very precisely made glass lenses, it takes the minutely separated light rays coming from something tiny (like a fly's eye) and spreads them apart so they appear to be coming from a much bigger object.
The optical or light microscope uses visible light transmitted through, refracted around, or reflected from a specimen. Light waves are chaotic; an incandescent light source emits light waves traveling in different paths and of varying wavelengths. Some of the lenses in a