What is an electron microscope?

A microscope is similar to a telescope or a pair of eye glasses. All microscopes, telescopes, and glasses have something in common, lenses. A lens is normally a curved piece of glass that bends the light that passes through it, think of a magnifying glass. Similar to how eye glasses makes things that are blurry and how telescopes make things that are far away seem close up, microscopes make things that are very small seem larger.
Below is an example of how light waves bend through different kinds of lenses:

Source: http://www.shokabo.co.jp/sp_e/optical/labo/lens/lens.htm

Light microscopes used in a number of areas such as medicine, science, and engineering. Microscopes that use light are powerful tools, but they cannot see the very small objects like atoms. For this, we can use an electron microscope, a microscope that uses electrons rather than light.

Source: http://www.microscopy.ethz.ch/lens.htm

Since electron microscopes do not use light, it also does not use typical lenses. Instead, it uses magnets. Just as lenses bend lights, magnets will make electrons bend. Since you cannot see electrons with your eyes, we use some other equipment to make a television signal that shows an image on a tv screen. The tv at your home uses electrons to produce an image as well. An electron microscope is kind of like a tv attached to some magnets!