Transcript The Microscope

Lab 2, BIO 105
The Microscope
• Essentially a magnifying device
– YOU MUST BE COMFORTABLE WITH USING THIS
• Two basic styles
– monocular
– binocular
• Eyepiece lens– usually magnifies ten times (10X)
– eye dominance
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• Revolving nose piece with objective lenses at end
– has 3 different lenses
– 4x (SCANNING or low), 10x (medium/working),
40x (high-dry)
– some scopes have a 100x lens which is also called
oil immersion lens because requires drop of oil to
help clarify image
• Stage: platform on which to place slide
– use clamp to hold slide in place
• Focusing knob: moves stage forward or backwards
and right to left
• Coarse adjustment knob**
– **only use this with the 4x lens
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• Fine adjustment knob
– be careful when using this--can damage slide
• Parfocal our scopes have the ability to remain in
focus when you switch to the higher lens; so
DON’T MOVE THE COARSE OR FINE
ADJUSTMENTS WHEN CHANGING LENS
• Light- can be bright or dim by moving the lever on the
iris diaphragm
• If light too bright, dim it—don’t let a bright light cause pain
• Condenser (allows you to move the light source
closer or further away)
– Organizes the light so the entire field has the same amount
of light
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• MAGNIFICATION
– always begin with the lowest magnification lens
(4x)
– get object in focus and centered
– objects have best depth of field or depth
perception in lowest magnification, AND also
have widest size of field (area you are viewing)
• Remember that as you increase magnification, you
are looking at a smaller part of your slide specimen
– so, center your specimen so you can find it in the
higher power
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• Cleaning and caring for the microscope
– if something is blurry, eyepiece and lens may
be dirty
• ONLY use lens paper to clean
– lens is delicate; don’t want to scratch it
– use 1 drop of liquid on lens paper and gently
rub onto eyepiece and lens
– dry lenses with another piece of lens paper
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Microscope - 2
• Putting your microscope away
– wrap cord around your hand and place over
ocular tube
– cover with dust cover
– use two hands to hold the arm of the
microscope and under the base to place it back
in cabinet
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LAB EXPERIMENTS
1.
2.
3.
4.
5.
Omit the size of the microscopic field activities
Identify and name all the parts of a microscope
State how to use and care for the microscope
Do the letter “e” observation
Use the crossed threads slide to understand depth
perception with a microscope
6. Examine an epithelial cell slide—do the wet mount
cheek slide following the directions in your lab
manual
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