Microscope History and
Development
Hans and
Zacharias
Janssen,
~1590, Dutch Eyeglass
Makers, Inventors
The first compound microscopes
produced by the Janssen's was
simply a tube with lenses at each
end. The magnification of these
early scopes ranged from 3X to 9X,
depending on the size of the
diaphragm openings.
Background
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14th century lenses were
used in spectacles
Late 16th century the Dutch
refined the art of lens
grinding  significant
magnification.
1600s – lenses first mounted
on permanent frameworks
(so distance could be
changed) This is important
to focus the image
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Next, lenses were
paired together.
These formed the
earliest compound
microscopes and
telescopes. This
increases the
magnification.
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.
Illustration of Cork Cells by Robert
Hooke
http://askabiologist.asu.edu/research/buildingblocks/rhooke.html
In Micrographia (1665), Hooke used 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.
Early Microscopes Anton Van Leeuwenhoek
(1632-1723).
 Anton Van Leeuwenhoek was the first to
see and describe bacteria (1674), yeast
plants, the living things in a drop of water,
and the circulation of blood corpuscles in
capillaries.
Anton van Leeuwenhoek, 16321723,
Leeuwenhoek made simple (one
lens) microscopes. He was not the
first person to build a microscope,
but the microscopes that he did
build were the best ones for that
time period. Leeuwenhoek was
the first person to describe
bacteria (from teeth scrapings),
protozoans (from pond water),
helped to prove the theory of
blood circulation. He gained much
of his inspiration from reading
Hooke's Micrographia.
Anton van Leeuwenhoek
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refined lens grinding
so that living things
could be seen
through the
microscope.
Then there was little
change until the
industrial revolution
Leeuwenhoek’s
primitive one lens
microscope.
Technological Advances in
Microscopes
Compound Light Microscopes
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Uses light
Has two lenses
Magnification limited to 2000x (400x at
LHHS)
Monocular Compound
Microscope
Binocular Compound
Microscope
http://www.ascoindia.com/pc
at-gifs/products-small/ms351.jpg
http://www.labessentials.
com/Rev3.jpg
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)
Van Leeuwenhoek used his new
instrument, which was ten times more
powerful than Hooke´s (he reached the
amazing power of 300 times with a
single lens) to discover startling
microscopic things, such as protozoa
and spermatozoa, which thus far were
completely unknown to science, or to
discover the microscopic structure of
known things, such as fleas and plant
leaves.
Changes of the Industrial
Revolution
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standardized parts (which were
interchangeable with other microscopes)
lead to mass production
This triggered a drop in price 
increased access  new discoveries 
clearer images
In approx. 1880  modern microscopes
were being used
Electron Microscope
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Developed in the 1930s
the electron microscope allowed for higher
magnification
used electron beams (instead of light) and
focused with an electromagnet (no lenses)
the light microscope produces magnifications up
to 2000X
the electron microscope produces images that
are magnified up to 50 000X or higher
The electron microscope allowed scientists to
see better quality images at higher magnification
Electron Microscope
Termite Head:
http://alfa.ist.utl.pt/~cvrm/staff/vr
amos/SIP.html
http://www.phy.cuhk.edu.hk/cent
rallaboratory/CM120/CM120.html
Spider ---- http://semguy.com/gfx/spidey.jpg