The Microscope

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The Microscope
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The First Light Microscope

• ANTON VAN LEEUWENHOEK was the first person to
  have a major contribution in the development of
  the microscope.
• He ground and then polished a ball of glass into
  a lens that had a magnification of about 270X!!
• He attached the lens to a metal holder and
  focused on specimens using small metal screws.

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SIMPLE MICROSCOPE

• Because his microscope had only one lens, it is
  referred to as a SIMPLE MICROSCOPE.
• With his simple microscope, Leeuwenhoek made many
  discoveries about things we cannot see including
  bacteria, human blood cells, and sperm!!

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COMPOUND MICROSCOPE

• The COMPOUND MICROSCOPE was eventually invented
  in order to get higher and higher magnifications.
  
• It uses a combination of two lenses and the total
  magnification is the product of the two lenses.
• Example Ocular (10X) x Objective (40X) 400X
  Total Magnification

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COMPOUND MICROSCOPE
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ROBERT HOOKE

• He was the first scientist to use the word
  CELLS after viewing a thin slice of cork under
  a compound microscope. He thought they looked
  like tiny jail cells.
• The cells he was looking at were really dead and
  all that remained were the rigid cell walls that
  were composed of CELLULOSE.

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ROBERT HOOKES MICROSCOPE
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MAGNIFICATION RESOLUTION

• MAGNIFICATION on a microscope is what makes the
  specimens appear to be larger.
• RESOLUTION on a microscope gives us the ability
  to distinguish fine details in a specimen.

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Images Produced by Light Microscopes
Amoeba
Streptococcus bacteria
Anthrax bacteria
Plant cells
Human cheek cells
Yeast cells
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PARTS FUNCTIONS OF THE MICROSCOPE

• See Double-Sided Handout.

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Beyond Light Microscopes

• Light microscopes are limited by their
  resolution.
• Light microscopes cannot produce clear images of
  objects smaller than 0.2 micrometers
• The electron microscope was invented in the
  1930s by Max Knott and Ernst Ruska
• Electron microscopes use beams of electrons,
  rather than light, to produce images
• Electron microscopes can view objects as small as
  the diameter of an atom

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Types of Electron Microscopes

• Transmission electron microscopes (TEMs) pass a
  beam of electron through a thin specimen
• Scanning electron microscopes (SEMs) scan a beam
  of electrons over the surface of a specimen
• Specimens from electron microscopy must be
  preserved and dehydrated, so living cells cannot
  be viewed

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Images Produced by Electron Microscopes
Cyanobacteria (TEM)
Lactobacillus (SEM)
Campylobacter (SEM)
Deinococcus (SEM)
Avian influenza virus
House ant
Yeast
Human eyelash
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Using Microscopes to Visualize the Three Shapes
of Bacteria

• Cocci (round)
• Bacilli (rod)
• Spirilla (spiral)
• Light microscope

Three shapes of bacteria taken with an SEM
Spirilla
Bacilli
Cocci
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References

• http//education.denniskunkel.com/catalog/product_
  info.php?products_id1123
• http//micro.magnet.fsu.edu/
• http//inventors.about.com/library/inventors/blrob
  erthooke.htm