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Unformatted text preview: imens. They are prepared as follows:
1. Place a single drop of water or other mounting liquid on the center of a microscope slide.
2. Place the sample upon the surface of or into the mounting liquid as specified. Grasp the
opposite edges of a single cover slip between your thumb and forefinger. Be careful here,
coverslips are quite thin and easily broken.
3. Touch the outer free edge of the cover slip to the slide surface at a point close to the drop.
While holding the edge of the cover slip against the slide and slightly angled from the slide
surface, move the slide toward the drop until they touch - the meniscus of the drop should
“grab” the cover slip.
4. Slowly lower the cover slip onto the drop and release it from your grasp as the cover slip
approaches the slide.
Perfusion of stains under a cover slip:
An easy way to apply aqueous stains to a slide that has been “cover-slipped” is as follows:
1. Apply a full drop of your stain to the slide surface at the edge of the cover slip - be careful not
to get the stain on the top of the cover slip.
2. Place the edge of an absorbent material, such as a small piece of a paper towel, against the edge
of the cover slip opposite to that which you applied the stain. This should pull some of the
stain under the cover slip.
3. Blot off any excess stain. Biology 05LA – Fall Quarter 2012 Lab 1 – page 11 Learning Goals/Desired Outcomes for Lab 1.
1. Be able to identify and properly name each of the microscope parts listed below and to describe the
specific function of the parts shown in bold using appropriate terminology.
a. ocular lenses b. base c. diopter ring d. brightness control e. binocular eyepiece tube f. light source g. arm h. revolving nosepiece i. stage j. objective lenses k. movable slide clamp l. condenser lens m. stage motion controls n. condenser focus o. coarse focus control p. condenser mounting bracket q. fine focus control r. condenser diaphragm and lever 2. Be able to routinely utilize all of the microscope use procedures described here.
3. Be able to safely clean the ocular and higher power objective lenses.
4. Be able to adjust the inter-ocular distance and the oculars (diopter ring) for comfortable viewing.
5. Be able to describe how the objective and ocular lenses interact to form the magnified image that the
6. Be able to describe the relationship between resolving power and numerical aperture.
7. Be able to describe what the condenser lens does and how an improperly focused condenser can
influence both image quality and the usefulness of the condenser diaphragm.
8. Be able to define the following terms: resolving power, depth of field, working distance, parfocal
(parfocality), contrast, differential staining.
9. Be able to describe how the following microscope parameters change as one moves from the lowest
power objective to the highest power objective: (1) resolving power, (2) depth of field, and (3) working
10. Be able to define, in your own words, the term “contrast”.
11. Be able to define, in your own words, the term “differential staining”
12. Be able to give a positive and a negative aspect of using the condenser diaphragm to increase contrast.
13. Be able to give a positive and a negative aspect of using differential staining to increase contrast.
14. Be able to respond to any questions relating to the “15 Mistakes” table presented on the next page. Biology 05LA – Fall Quarter 2012 Lab 1 – page 12 15 Mistakes Commonly Made by Beginning Microscopists
and the Consequences of These Mistakes.
Attempting to rotate the fine focus control
beyond its limited range of movement.
Moving the microscope stage upward with the
coarse focus control while looking through the
Not positioning the low power objective in the
light path before changing slides.
Leaving the high power objective in the light
path when returning ‘scope to storage. 5. Not centering the mechanical stage assembly
before returning ‘scope to storage.
6. Changing magnification by pushing or pulling
on the objectives rather than by rotating the
grooved edges of the revolving nosepiece.
7. Not carrying microscopes to and from the
storage area with two hands and in an upright
8. Loosening the screw that secures the eyepiece
tube onto the microscope arm.
9. Improper use of the stage clamp. 10. Lowering the stage when changing slides or at
the end of a microscopy session.
11. Not beginning all observations with the low
12. Improper focus of condenser. CONSEQUENCES
This can strip the gears that drive the focusing
This can result in hard contact between the objective
and slide resulting in damage to either or both.
This can result in damage to the high power
The high power objective could be damaged.
The mechanical stage assembly could be damaged if
the protruding portion is banged against the side of
the storage cabinet.
The objective lenses can become loose if handled in
this manner resulting in a loss of the ‘scop...
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- Fall '12