17th Century Microscopy

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17th Century Microscopy

• Simple microscopes
• magnifying glasses
• single lens
• limited by quality of lens and light

Simple microscopes.
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17th Century Microscopy

• Compound Microscopes
• Hans and Zacharias Janssen
• invented first compound microscope
• Robert Hooke
• looked at cork
• many common materials

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18th Century Microscopy

• Antoni van Leeuwenhoek
• built over 500 microscopes only about 3 to 4
  inches long with a single lens
• viewed animalcules or beasties
• bacteria
• spermatazoa
• red blood cells

Leeuwenhoek
A beastie perhaps observed by Leeuwenhoek.
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19th Century Microscopy

• Advances due to improved lenses
• Theodore Schwann
• cell is basic unit of life

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19th Century Microscopy

• Advances due to improved light technology
• Solar microscope
• ultraviolet microscope
• ultraviolet fluorescence microscopy
• J.J. Thompson in 1897
• discovered the electron

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20th Century Microscopy

• Max Rushka in 1931
• Transmission Electron Microscope (TEM)
• VERY thin specimen
• Can not use living specimens

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20th Century Microscopy

• Dennis McMullan in 1948
• Scanning Electron Microscope (SEM)
• metallic coated specimen that reflected back
  electrons
• 3-dimensional image
• can not use live specimens

SEM images provide 3-D details of the specimens
surface.
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20th Century Microscopy

• Heinrich Rohrer and Gerd Binnig in 1982
• Scanning Probe Microscope (SPM)
• extends the sense of touch
• 1986 Nobel Prize with Max Rushka

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Scanning Probe Microscopy

• Scanning Tunneling Microscope (STM) in 1982
• Atomic Force Microscope (AFM) in 1985

Atomic Force Microscope used at IN-VSEE lab.
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Scanning Probe Microscopes
Use the sense of touch to create images .
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Scanning Tunneling Microscope

• Requires an electrically conductive sample
• Small current will flow between tip and sample
  surface
• Current changes with the height of sample and
  image is produced on this change

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Atomic Force Microscope (AFM)

• Can be used to look at non-conductive samples
• bacteria and viruses
• computer chips and CDs
• Probe moves over sample surface and reads
  repulsive force

Measures forces between atoms, between surfaces,
etc.
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Views by different microscopes

• Mushrooms can be seen with out any magnification.

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Views by different microscopes

• Cross-section through a mushrooms as seen with
  light microscopy.

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Views by different microscopes

• Mushrooms are composed of thread-like cells, like
  this seen at a higher power with a light
  microscope.

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Views by different microscopes

• Organelles in the cell are more obvious in a TEM.

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Views by different microscopes

• Using SPM, the 3-D surface of the spore-producing
  basidium can be visualized.

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Views by different microscopes

• The bud scars of a different kind of fungus, a
  yeast cell, can be be visualized using SPM.

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Snake images
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Mussel sea shell images
Fibrous texture of shell surface seen with SEM.
Fibers at higher SEM magnification.
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Mother of pearl sea shell images
Layers of plates in the shell SEM image.
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AFM images
Horse hair.
Gold film.
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AFM images
Bacterium from a dog dish.
Tungsten.
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STM images
CD-ROM surface.
Video tape surface.