Scanning Electron Microscopes provide three-dimensional views of the specimens. An electron gun produces a finely focused beam of electrons known as a primary electron beam. These electrons pass through electromagnetic lenses and are directed over the surface of the object to be seen. The primary electron beam knocks electrons out of the surface of the specimen resulting in the production of secondary electrons that are transmitted to an electron collector, amplified, and used to give an image on the viewing screen or photographic plate.
The scanning electron microscope is used to study surface features such as that of leaf peelings, pollen grains, fungal spores, and bacteria.