What is an Electron Microscopy?
Electron Microscopy What is an Electron Microscopy? Microscopes are used to look at objects that cannot be seen by the naked eye. There are two types of microscopes: light microscopes which use light to see the image these microscopes use lenses and light to project the image in to the eye, and the second are electronic microscopes these use electrons and magnets to project an image on to a fluorescent screen since electrons can not be seen by our eyes. How does it work? . Electrons are fired from an electron gun. 2. Electrons then travel through a vacuum. 3. They go through the specimen and objective lens. 4. The electrons then hit a flourescent screen and make light. 5. The light makes a picture (electron micrograph), which is visible to the human eye. Electrons can be affected by such as air molecules that's why they have to travel through a vacuum and that's why a fluorescent screen is used because they cannot travel trough glass. Advantages * Small wavelength gives better resolution. * They produce sharp definition. * They can focus using magnets so can get very good micrographs. Disadvantages * Very expensive. * Very big. * Sometimes artefacts are made (not what is in the specimen can be seen) * Hard to cut specimen so thin. * Sometimes electrons do not pass. * Living specimens cannot be seen. * Must be stained in very