Question

how a microscope work

Answer 1

Microscopes are effectively just tubes packed with lenses, curved pieces of glass that bend (or refract) 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.

So what does a microscope actually do? Imagine a fly sitting on the table in front of you. The big, fat, compound eye on the front of its head is just a few millimeters across, but it's made up of around 6000 tiny segments, each one a tiny, functioning eye in miniature. 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). Your eyes may be good, but they're not that good. To study a fly's eye really well, you'd 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.