Microscopes

• Compare optical and TEM work and their limitations

  • an optical use a beam of light whereas TEM uses a beam of electrons
  • optical is a long wavelength whereas TEM is a short wavelength beam
  • TEM sample in vacuum whereas optical not (only dead in TEM and optical can view live)
  • TEM sample needs to be thinner whereas optical doesn’t have to be as thin
  • TEM has high resolution and mag whereas optical has low (so smaller organelles an be observed by TEM)
  • TEM doesn’t show colour and optical can
  • TEM is more time consuming preparation
• Compare a TEM and a SEM

  • both in a vacuum
  • both use short wavelength electron beam and magnets to direct beam
  • TEM requires thin specimen and SEM don’t
  • TEM has a higher resolving power than a SEM