Electron Microscope Unit
Explore this Section
Overview - Electron Microscope
Electron microscopes (EM), surprisingly, are pretty much the same as light microscopes! They use a beam of electrons rather than light, but have objective lenses like a light microscope. The big difference is that very few things are transparent to an electron beam, unlike light. Even normal air will stop the beam very quickly and it cannot travel through glass at all. Inside the electron microscope is a vacuum, which allows the beam to travel, and all the lenses are made from a coil of copper wire around a magnet, with a central hole for the beam to pass through. Because these lenses are quite big, and because of all the special valves, pumps and other things needed to maintain the vacuum, an electron microscope is bigger than a light microscope, and usually upside down because the electrons come from a special gun at the top.
The two types are transmission or TEM (equivalent to a compound light microscope) and scanning or SEM (equivalent to a zoom microscope).
