How does a microscope work?

A microscope magnifies tiny objects using a system of lenses (or electron beams). In an optical microscope, a light source illuminates the sample (often via a condenser lens), and an objective lens gathers light from the sample to produce an enlarged image. This real image is further magnified by the eyepiece for your eye. The lenses refract (bend) light, spreading apart rays from adjacent points so they appear separate when enlarged. Electron microscopes use focused electron beams and electromagnetic "lenses" to achieve much higher resolution. In all cases, microscopy turns minute detail into a resolvable image by optically expanding it.