3 Microscopes

  • Created by: lee8444
  • Created on: 31-01-20 10:34

Microscopy, Resolution and Magnification


  • Glass that is convex acts as a magnifying glass
  • Compounded, convex glass is far more effective
  • Light microscopes have a resolution of 0.2 micrometres
  • Electron microscopes have a resolution of 0.1 nanometres


  • The minimum distance apart that two objects can be whilst still sistinguishable as different objects
  • Depends of wavelength of the radiation
  • Greater resolutions means greater clarity

Size of image = magnification x Size of real object

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The Electron Microscope

  • First made in the 1930s
  • Very short wavelength
  • Focused using electromagnets
  • 200 times greater resolution than the light microscope
  • Needs a vacuum to stop the deflection of electrons
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  • Electron gun produces a beam of electrons through a specimen
  • Specimen has to be thin for the electrons to pass through
  • Resolution of 0.1nm
  • Thinner parts allow electrons through and appear lighter on the screen


  • Electrons are fired from above
  • Electrons are reflected and scattered
  • This scattering depends on the surface of the specimen
  • 3D image is produced
  • Lower resolution of 20nm
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  • High energy electron beam may destroy the specimen
  • Vacuum doesn't allow lioving specimens
  • Staining process is complicated
  • Not in colour
  • Slow
  • TEM is 2D
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