2 The Principle of the Electron Microscope

How to Make a Microscope, Chapter 2 Unlike the optical microscope, the scanning electron microscope uses accelerated electrons in a vacuum to act as light to view the sample. An electron is the negatively charged particle of an atom orbiting around a nucleus. It can be released by heat or an electric field. Electrons are 2,000 times lighter than the smallest atom, thus they can be easily stopped or diverted when striking materials. Because electrons move freely only in a vacuum, there must be a vacuum in t