A Bit of History ofthe Microscope

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Clipart from Microsoft Office Online

The microscope got it’s

name because it

allows us to view minute

things.

Micro means very small.

Scope (suffix) means

viewing or observing.

.

History of the microscope

Spectacles were known in Italy in

1200

The early simple “microscopes” which were really only magnifying glasses had one power, usually about 6X - 10X . One thing that was very common and interesting to look at was fleas and other tiny insects. These early magnifiers were hence called “flea glasses”.

Around 1590, two Dutch spectacle makers, Zaccharias Janssen and his father Hans started experimenting with these lenses. They put several lenses in a tube and discovered objects were greatly enlarge. This was thefirst compound microscope.

Anthony Leeuwenhoek of Holland (early 1700’s) became very interested in lenses while working with magnifying glasses in a dry goods store. He used to count the threads in cloth.

He taught himself new methods for grinding and polishingtiny lenses which gave him greater magnifications.has since been called the "Father of Microscopy"

Robert Hooke’s

Microscope

Hooke wanted to know what something living looked like when it was strongly magnified. Since he knew that he would need to cut a really thin layer to view through his microscope, he chose to view a piece of easily-sliced cork tree…

Hooke’s microscope

http://en.wikipedia.org/wiki/Image:Hooke_Microscope-03000276-FIG-4.jpg

Cork oak (Quercus suber) with

sections of cork removed

Eric G. Carle—Shostal/EB Inc.

This is a photograph of a cork tree (from which we cut cork).

Cork

http://en.wikipedia.org/wiki/Image:Cork_Trees_Ubrique.jpg

When Hooke

viewed the thin layer of

cork through

his micro-scope, this is

what he saw:

http://upload.wikimedia.org/wikipedia/commons/1/17/Cork_Micrographia_Hooke.png

The small structures that “make up” cork reminded Hooke of the prison cells of his century…

What Hooke saw through his scope…

Modern Prison Cells

http://upload.wikimedia.org/wikipedia/commons/1/17/Cork_Micrographia_Hooke.png http://en.wikipedia.org/wiki/Image:Oxford_Castle.JPG

http://en.wikipedia.org/wiki/Image:Prison_cell.jpg

…so he named the small structures “cells.”

Cork Cells

(Cells from a Cork Tree)

Modern Prison Cells

http://upload.wikimedia.org/wikipedia/commons/1/17/Cork_Micrographia_Hooke.png http://en.wikipedia.org/wiki/Image:Oxford_Castle.JPG

http://en.wikipedia.org/wiki/Image:Prison_cell.jpg

Schleiden and Schwann

•

http://upload.wikimedia.org/wikipedia/commons/a/ab/Matthias_Jacob_Schleiden.jpg

Proposed cell theory:

1. All living things are composed of cells2. Cells are the basic unit of structure and function in living things3. All cells are produced by other cells

Microscopes use a lightsource. The light source is a light-bulb located at the base of themicroscope. The light source lightsup the specimen by passing lightthrough a thin, almost transparentpart of the specimen.

Microscopes are compound, meaningthey have two or more lenses usedto magnify objects. These lenses bendthe light.

1931- An electron microscope depends on electrons rather than light to view an object. Electron microscopes make it possible to view objects slightly larger thanan atom.

In effect, it can magnify objects up to 1 million times. Nevertheless, all electron microscopes suffer from a serious drawback. Since no living specimen can survive under their high vacuum, they cannot show the ever-changing movements that characterize a living cell.

Magnification: X 1,000

Mosquito head

Magnification: X 200

Black Widow Spider Claw

Moth wing

Cucumber Skin

Staple through paper

Toilet paper

Hypodermic Needle

Foot of a House Fly

Deer Tick

Microscope Rules

1. Always use two handsto carry a microscope!

One hand goes under the baseand one on the arm.

2. Do not touch the lenses. If they are dirty, ask your teacher for special lens paper or ask the teacher to clean the lenses for you.

3.Be cautious when handling glass slides. Notify teacher if a slidebreaks. Students should not handle broken glass.

Microscopes are not toys!!

They are expensive tools!!