Name ____________________________________________________ Date ___________________
Dissecting/Stereo Microscope
The stereo or dissecting microscope is an optical
microscope variant designed for low magnification observation of a
specimen. It typically uses light reflected from the surface of an object
rather than transmitted through it as a compound microscope does.
The dissecting/Stereo microscope uses two separate optical paths
with two objectives and eyepieces to provide slightly different viewing
angles to the left and right eyes. This arrangement produces a threedimensional visualization of the specimen
1. Examine the dissecting/stereo microscope. Working with a partner, find as
many differences between a compound microscope and a dissecting
microscope and list them here:
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2. Fill in what these parts do:
Microscope Part
a. Eye Piece
b. Rotating Objects
c. Stage plate
d. Focus knob
e. Lighting controls
Function
3. Choose an object or an organism to explore under the stereo microscope
on the lab desk.
4. Sketch the organisms seen under the stereo microscope. Follow the rules
of scientific drawing:
a. Draw only what you see! Do not include what you think you should see.
b. All drawings must be done in pencil ONLY.
c. Drawings must be large and clear so that features can be easily
distinguished.
d. Always use distinctive drawings, do not sketch.
e. Give your drawings a title, write the magnification and label important
features.
Title ___________________________ Magnification _________________
Title ___________________________ Magnification _________________
Title ___________________________ Magnification ________________
Title ___________________________ Magnification _________________
Short History of the Microscope
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Pre-1600: In the 11th century, the Arab Alhazan described the
use and characteristics of glass lenses. Two hundred years
later, the English natural philosopher Roger Bacon was familiar
with lenses. Eyeglasses, however, were not invented until the
late 1200s.
1600s: In 1608 the telescope was invented, with Galileo
improving upon it with his own models. Around 1600, the
microscope was invented, possibly by Hans and Zacharias
Jansen. Due to poor lens quality, the early compound
microscopes (ones that used two lenses) could only magnify an
object up to 20 or 30 times its normal size.
The first big microscopy advances came in 1665, when Robert Hooke
published the Micrographia, a collection of copper-plate illustrations
of objects he had observed with his own compound microscope. He
coined the term "cell" when looking at a piece of cork under 30x
magnification.
In the late 1660s, Antony van Leeuwenhoek began to grind his own
lenses and make simple microscopes. Each microscope was really a
powerful magnifying glass rather than a compound microscope.
Leeuwenhoek's hand-ground lenses could magnify an object up to
200 times! He observed animal and plant tissue, sperm cells and
blood cells, minerals, fossils, and much more. He also discovered
nematodes and rotifers (microscopic animals), and he discovered
bacteria while looking at samples of plaque from his own and others'
teeth.
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1700-1800s: Not much change in the basic microscope design
occurred, but better lenses were crafted (using purer glass and
different shapes) to solve problems like color distortion and
poor image resolution. In the late 1800s, Ernst Abbe discovered
that oil-immersion lenses prevented light distortion at highest
magnification power. These are still used today on 1000xobjectivemicroscopes.
1900s till now: In 1931, a pair of German scientists invented
the electron microscope. This kind of microscope directs a
beam of speeded-up electrons at a cell sample; as the
electrons are absorbed or scattered by different parts of the
cell, they form an image that can be captured by an electronsensitive photo plate. This model enables scientists to view
extremely small parts, magnified as much as one million times.
The only drawback is that living cells can't be observed with
electron microscopes. However, compound microscopes are
being improved with digital and other new technology, making
microscopy better for everyone from kids to lab microbiologists.
Flea Image using an Electron Microscope
Mascara Brush with dried skin cells under the Electron Microscope