Transcript Microscope History and Development

Microscope History and
Development
(2)
Field of view and Magnification
Check and go over yesterday’s HW p 140-1
Early Microscopes Anton Van Leeuwenhoek
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The father of microscopy, Anton Van
Leeuwenhoek of Holland (1632-1723).
Anton Van Leeuwenhoek was the first to
see and describe bacteria (1674), yeast
plants, the teeming life in a drop of
water, and the circulation of blood
corpuscles in capillaries.
Robert Hooke
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In 1665, the English physicist Robert
Hooke looked at a sliver of cork through
a microscope lens and noticed some
"pores" or "cells" in it.
Hooke was the first person to use the
word "cell" to identify microscopic
structures when he was describing cork.
Antique microscopes (link)
Technological Advances in
Microscopes
Compound Light Microscopes
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Uses light
Has two lenses
Magnification limited to 2000x (400x at
LHHS)
Transmission Electron Microscope
(TEM)
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Uses beams of electrons
Magnification of 2 000 000x
Has two limitations:
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Good only for thin specimens
Only dead cells can be observed
Scanning Electron Microscope
(SEM)
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Electrons are reflected from the
surface of the specimen
Produces a 3-d image
Good for the thicker specimens
Lacks the magnification and resolution
of the transmission electron microscope
Magnification
Magnification = Objective lens X Ocular lens
(4x, 10x, 40x)
(10x)
Calculating the size of a specimen
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binder
Calculating the size of a specimen
Example under med. objective
Object size =
Size of field of view
Number of objects
across field of view
Object size =
1.72 mm
14
Object size =
0.1 mm