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Microscope History and Development

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Title: Microscope History and Development


1
Microscope History and Development
2
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.

3
Background
  • 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

4
  • Next, lenses were paired together.
  • These formed the earliest compound microscopes
    and telescopes. This increases the magnification.

5
Robert Hooke
  • 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.

6
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7
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8
Illustration of Cork Cells by Robert Hooke
http//askabiologist.asu.edu/research/buildingbloc
ks/rhooke.html
9
  • 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.

10
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.

11
Anton van Leeuwenhoek, 1632-1723,
  • 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.

12
Anton van Leeuwenhoek
  • refined lens grinding so that living things could
    be seen through the microscope.
  • Then there was little change until the industrial
    revolution

Leeuwenhoeks primitive one lens microscope.
13
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14
Technological Advances in Microscopes

15
Compound Light Microscopes
  • Uses light
  • Has two lenses
  • Magnification limited to 2000x (400x at LHHS)

16
Monocular Compound Microscope http//www.ascoindia
.com/pcat-gifs/products-small/ms-351.jpg
Binocular Compound Microscope http//www.labessent
ials.com/Rev3.jpg
17
Transmission Electron Microscope (TEM)
  • Uses beams of electrons
  • Magnification of 2 000 000x
  • Has two limitations
  • Good only for thin specimens
  • Only dead cells can be observed

18
Scanning Electron Microscope (SEM)
  • 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

19
Magnification
  • Magnification Objective lens X Ocular lens
  • (4x, 10x, 40x) (10x)

20
  • Van Leeuwenhoek used his new instrument, which
    was ten times more powerful than Hookes (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.

21
Changes of the Industrial Revolution
  • 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

22
Electron Microscope
  • 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

23
Electron Microscope
Termite Head http//alfa.ist.utl.pt/cvrm/staff/v
ramos/SIP.html
http//www.phy.cuhk.edu.hk/centrallaboratory/CM120
/CM120.html
24
Spider ---- http//semguy.com/gfx/spidey.jpg
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