Electron Microscopes

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Electron Microscopes
Use electrons instead of light to form images.
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Light Microscopes
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Light Microscopes

• Unknown when first invented, but probably between
  1590-1610 A.D.
• Can magnify up to 1000 x
• Shines light through an object and projects the
  image through a series of lenses that magnify the
  image.
• Relatively inexpensive

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Uses

• Great for studying live microscopic organisms.
• Great for studying cells and tissues in general.
• Widely used in hospitals and clinics to diagnose
  disease.

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Example images using light microscopes
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Example images using light microscopes
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Example images using light microscopes
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Transmission Electron Microscope(TEM)
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Transmission Electron Microscope(TEM)

• First invented in 1931 (in Germany)
• Can magnify up to 200,000 x (and beyond)
• Similar to a light microscope except that a beam
  of electrons is used instead of light. The
  electrons that penetrate through the object and
  create an image which is then enlarged and then
  viewed on a computer monitor.
• Samples of the object must be sliced very thin
  before using the TEM. (No living specimens.)
• Very expensive and time consuming to prepare
  slides.

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Uses of the TEM

• Used in biological/medical research to
  investigate parts of cells and molecules.
• Used in material science to study the structure
  and the weaknesses of crystals.
• Used in nanotechnology.

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Example images using TEMs
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Example images using TEMs
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Example images using TEMs
Nanotubes
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Example images using TEMs
Marburg virus
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Scanning Electron Microscope(SEM)

• http//www.mos.org/sln/SEM/

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Scanning Electron Microscope(SEM)

• First invented in 1942
• Can magnify typically up to 10,000 x
• Gives a 3D image of the surface of the object
• Again, a beam of electrons is used instead of
  light. The electrons that bounce off the object
  create the image. The microscope scans a certain
  region of the object multiple times and then
  combines multiple images to create what we then
  see on a computer monitor as one 3D image.
• No slicing needed so easier to prepare samples.
  Larger objects can be viewed.
• Very expensive.

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Uses of the SEM

• Multiple uses - for viewing the surface of any
  microscopic object.
• Insect parts
• Bacteria
• Food industry
• Material science
• Education
• Art

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Example images using SEMs

• Mascara brush

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Example images using SEMs

• Moth antennae

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Example images using SEMs
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Practice Quiz

• Now look at the following images. Determine
  which type of microscope produced each image and
  write your answers down on a piece of paper.
• LM Light Microscope
• TEM Transmission Electron Microscope
• SEM Scanning Electron Microscope

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Mosquito
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