Electron microscope has two main advantages:
- Electron beam has v. short wavelength, can resolve objects well.
- Electrons are negatively charge, beam can be focused using electromagnets.
- Some can resolve objects just 0.1nm apart
However, electrons are absorbed by molecules in the air so near-vacuum must be created.
Transmission Electron Microscope (TEM)
- Consists of electron gun that produces beam of electrons, focused onto specimen by condenser electromagnet.
- Beam passes through thin section of specimen - parts absorb electrons and appear dark, others allow electrons to pass through and appear light.
- Image produced on a screen, can be photographed to give a photomicrograph.