Name ________________________________ Date _________ Period ______Number_____
Electron Microscopes
To complete this assignment, either type the web addresses into your browser or follow the links on
Mrs. Nuffer’s Moodle Page.
Part 1: MOS Scanning Electron Microscope
http://legacy.mos.org/sln/SEM/index.html
Click on the link for “How It Works” and read the information on that page.
1. The first light microscope was used in 1595 when Zacharias Jansen invented a compound
microscope that magnified up to 9X. Today’s most powerful light microscopes have magnifying
powers of 1,000 to 2,000X.
What is the highest magnification power of the scanning electron microscope shown?
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Click on the link for “Slide Show.”
2. What does SEM stand for? ____________________________________________________________
3. How do conventional light microscopes, like the ones we use in class, work? ________________
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4. What does the scanning electron microscope use to magnify images? _______________________
5. Why are the images black and white? __________________________________________________
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6. How does the SEM work? Proceed through the slides and put the steps in order from 1-8
________As the electron beam hits each spot on the sample, secondary electrons are knocked
loose from its surface, which are counted by a deflector and sent as signals to an amplifier.
________Biological samples have to be made capable of conducting electricity.
________The sample is placed inside the microscope’s vacuum column through an air-tight door
________ A set of scanning coils moves the focused beam back and forth across the specimen,
row by row.
________The final image is built up from the number of electrons emitted from each spot on the
Sample
________Air is pumped out of the column before the electron gun emits a beam of electrons,
which travels downward through a series of magnetic lenses designed to focus the
electrons to a very fine spot.
_______The Scanning Electron Microscope reveals new levels of detail and complexity in the
amazing world of microorganisms.
_______ SEM samples are coated with a very thin layer of gold by a machine called a sputter
Coater.
Part 2: Virtual Electron Microscope
http://school.discoveryeducation.com/lessonplans/interact/vemwindow.html
Click and drag the specimens on the left side under the microscope to examine. Then identify the
slides by dragging them to the correct spot on the right side of the screen. Write the name of each
sample below. Then write one fact about each specimen.
Name of Specimen
1
2
3
4
5
6
7
8
9
10
Fact about specimen