3.2 the electron microscope

• The electron beam has a very short wavelength and the microscope can therefore resolve objects well
• As electrons are negatively charged, the beam can be focused using electromagnets
• There are two types of electron microscopes:

  1. The transmission electron microscope
  2. The scanning electron microscope
• In the TEM, the beam penetrates the specimen, whereas the SEM directs the beam onto the surface
• Limitations of an electron microscope:

  1. Living species cannot be observed
  2. a staining process is required even tho the image isn’t in colour
  3. the specimen must be extremely thin
  4. the image may contain artefacts