Lab 4: The Compound Light Microscope
The micrometer slides and the microscope are expensive. Be careful—or this lab will end up costing you a lot of money. Check with me at the end, when returning either one.
Here is another photo of a scope:
Three important scope features:
Magnification: . might look like this: .
Resolution:
Contrast:
Cell size (most cells): Prok: 1-10 μm; eukaryotes: 10-100 μm
Anton van Leeuwenhoek (pronounced lā-vən-huk), the Galileo of biology: 17th century, first to develop a microscope, first to see bacteria, protists (mostly unicellular eukaryotes, e.g., amoeba), sperm—imagine his excitement!!!
Compound microscope (as opposed to simple) involves a series of lenses, magnifications.
Focal length (table, lab manual 4) measures how strongly light is focused. The shorter the focal length, the greater the optical power.
Working distance (p. 4): When a specimen is focused, distance from end of objective to the cover slip.
Depth of field: Distance in front of and beyond the specimen which is still in focus—the depth of what you can still clearly see.
Refraction, e.g., when light moves into a different medium (e.g., from air to water), the speed of light changes, thereby causing the light to change direction.
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Elodea (\i-lō-dē-ə\) (=water weed or pond weed); in nature, almost entirely submerged in water |
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Human cheek cells |
Onion thin section |
Vinegar eel |
amoeba |
