Videos of Proper
Note that you will need either
to view these files.
The QuickTime files clearly show details, but are larger and take longer to
download (both formats supposedly will stream the movies), while the
RealPlayer files are smaller in filesize but show far less detail.
The size of each file will display in the status bar as you put the mouse
over each picture, below.
The whole process of proper
microscope use is available as a QuickTime or RealPlayer video.
Or, to see a specific segment,
click on a picture to view the corresponding movie.
||Parts of the Microscope
your lab notebook, draw and label a picture of a microscope. Know what all
the parts are, where they are, and what they do.
||Getting out the Microscope
carrying a microscope, one hand goes under the base and one hand goes around
the arm of the microscope.
||Plugging in the Cord
should be draped over the table top, not left dangling down. Someone could
trip over a dangling cord and pull a microscope off the table.
||Adjusting Chair Height
your chair height so you can comfortably look through the microscope.
||Obtaining a Letter “e” Slide
how the letter “e” appears to the naked eye and how that differs from its
appearance under the microscope.
||Getting the Right-Eye View in Focus
the coarse and fine adjustment knobs to bring the right-eye view into focus.
||Getting the Left-Eye View in Focus
the diopter adjustment to bring the left-eye view into focus.
||Adjusting the Interpupillary Distance
the width between the oculars until you can comfortably see one image with
||Going from 4× to 10× Objective
going to a higher-power objective, do not move the stage. You may use either
the coarse or fine adjustment knobs at 10×.
||Going from 10× to 40× Objective
going to 40×, watch from the side to make sure the lens doesn’t hit the slide,
but do not move the stage. Only use fine adjustment at 40×.
||Putting Away the Microscope, Part 1
putting away your microscope, make sure to read the checklist on the back of
the microscope and do everything listed there.
||Putting Away the Microscope, Part 2
microscope should be placed in the cupboard with the arm facing toward you
so the next person can grab the arm to take the microscope out.
||The Microscope Police
microscope checks may occur after you leave the lab. Any problems will be
reported to your lab instructor and/or you may be graded on your technique
(a “pop” quiz).
Some “Easy” Microscope Repairs
- If the light doesn’t turn on, the first thing to try is to push the red
“reset” button on the outlet into which the cord is plugged. Also, check to
make sure the “problem” isn’t that the light is really on, but the rheostat
is set on #1, so it just “looks like” it’s not on. If you’ve tried both of
those, and that doesn’t help, then notify your instructor or the lab staff
(so they can check the fuse and bulb).
- If you can’t see your specimen because the view is too dark, try turning
up the rheostat and/or opening the iris diaphragm more.
- Unless it has been lost, there may be a blue filter under the iris
diaphragm, held in place by a black, plastic ring. Since that’s only held in
place by spring(s), occasionally, if it gets bumped (like when you’re trying
to wrap the cord?), it pops out. If that happens, just carefully pop it back
- Although you were told to not loosen the optical head retaining screw,
occasionally some other student in “one of those other classes” will do so.
Thus, if you find that someone else has left this screw loose, tighten it!
If someone left the optical head crooked, you may loosen the screw just a
tiny bit to straighten out the optical head, then make sure to tighten it,
- If the mechanical stage is loose and wobbly and slides are slipping under
the stage clip rather than it holding them securely, its screws are loose.
The mechanical stage is held in place by two “big,” silver-colored screws
under the stage, along the “right” edge. If those screws are loose and
need to be tightened, do so!
- If you’re looking through the microscope and you can see your specimen in
half the view, but the other half the view is dark, that probably means the
lens isn’t totally clicked into place. Rotate the nosepiece until the lens
is clicked into place.
- If you had your specimen in view and focused using the 4× objective and
the 10× objective, but then “lost it” when you went to the 40× objective,
there are two things you need to check. Go all the way back to the 4×
objective, and re-find and re-focus your specimen. Make sure the area you
wish to examine is exactly in the center – use the mechanical
stage controls to center it. Then, turn the nosepiece until the 10×
objective is in place and re-focus there. Again, insure that the area you
wish to view is exactly in the center. When you go to the 40×
objective, watch from the side to make sure it’s not going to hit, but
don’t move the stage down!!! The lens will come very close to the
coverslip, but it should just barely clear it, and if you move the stage way
down because you “think” it's going to hit, you’ll never find and be able to
focus on your specimen. If, indeed, the lens does come so close that it
won’t clear the coverslip, that means that you won’t be able to get that
specimen in focus with the 40× objective, and moving the stage down won’t
- If your specimen was in focus at 40× and 100×, but when you go to 400×,
you can see the specimen but can’t get it into focus, there are a couple
things to try. Assuming you’ve already tried the fine adjustment, the next
thing to check is the position of the iris diaphragm lever. If the iris
diaphragm is all the way open, you won’t be able to get much in focus – try
closing the iris diaphragm most of the way to see if that helps. Try moving
the condenser height adjustment knob, because changing that can help.
If you’ve tried making those adjustments, and that hasn’t helped, and your
image is still really blurry, there is a chance that “some student” in “one
of those other classes” got immersion oil on the 40× objective (which it’s
not designed for) and then didn’t clean it off (which “they” are supposed to
do). Get a piece of lens paper out of your drawer and use that to
clean the 40× objective (gently breathing on the paper can help). While
you’re at it, check the 100× oil-immersion lens too – chances are, if the 40×
is dirty, the 100× may be dripping oil that was never cleaned off. While
you don’t want to break the lenses in the process, you also don’t want to be
so “gentle” with them that you don’t do any good. The tips of the 40× and
100× lenses are
spring loaded, so they will “give” with sufficient, gentle pressure.
Things to Include in Your Notebook
Make sure you have all of the following in your lab notebook:
- all handout pages (in separate protocol book)
- all notes you take during the video and introductory mini-lecture
- all notes and data you gather as you perform the experiment
- drawing (yours!) of the microscope that you used in lab,
with all parts labeled and functions of those parts noted
- drawings (yours!) of letter “e” at various powers of
magnification (label which power, label silver crystals if seen)
- optional drawings (yours!) of slide and coverslip
- answers to all discussion questions, a summary/conclusion in your
own words, and any suggestions you may have
- any returned, graded pop quiz
Copyright © 2000 by J. Stein Carter. All rights reserved.
Based on printed protocol Copyright © 1986 D. B. Fankhauser
and © 1988 J. L. Stein Carter.
Chickadee photograph Copyright © by David B. Fankhauser
This page has been accessed times since 14 Mar 2001.