Introduction of Assisted Viewing Using Microscopes

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Introduction of Assisted Viewing Using
Microscopes
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The Microscope

• Microscope is the combination of two words
  "micro" meaning small and "scope" meaning view.

• Magnification the ratio of the image size to
  the size of the object.

• Light Microscope refers to the method by
  which light transmits the image to your eye.

• Compound deals with the microscope having
  more than one lens.

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Robert Hooke, 1635-1703, English Chemist,
Mathematician, Physicist, and Inventor
Hooke improved on early compound microscopes
around 1660. In Micrographia (1665), he coined
the word cell to describe the features of plant
tissue (cork from the bark of an oak tree) he was
able to discover under the microscope.
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How does a microscope work?
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Resolution - How close can two points in the
image be before they are no longer seen as two
separate points?

• Resolution is related to the numerical aperture
  of the objective lens and the wavelength of light
  passing through the lens

• The higher the numerical aperture, the better
  the resolution

• The shorter the wavelength, the better the
  resolution

Radiation wavelength
Resolution
Numerical aperture
Good resolution
Poor resolution
Image of a pollen grain by Craig C. Freudenrich,
Ph.D.
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Contrast - What is the difference in lighting
between adjacent areas of the specimen?

• Contrast is related to the illumination system
  and can be adjusted by changing the intensity of
  the light and the diaphragm/pinhole aperture.

• Also, chemical stains applied to the specimen
  can enhance contrast.

Good contrast
Poor contrast
Image of a pollen grain by Craig C. Freudenrich,
Ph.D.
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Parts
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Preservation Techniques for Invertebrates
Relaxation Design to calm or slow down specimen
before euthanizing

• Refrigeration/freezing

• Dilutions H2O, EtOH

Fixation - Process by reducing tissues from a
volatile or fluid form to a stable or solid form
Preservation - To protect and make resistant to
bacterial invasion and decomposition
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Labels and Records
Example of Insect Label

• Country, state and county
• Locality Lat/long, township range
• Habitat ie. Terrestrial or aquatic, desert scrub
  or grassland
• Method of capture malaise trap, pitfall trap,
  etc.
• Date/time of day, lunar phase
• Original preservative
• Collectors name First, M.I., Last,
• Collector note number (reference in a journal or
  notes of specimen)

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