Microscope Introductory Lab
1. Examine your microscope and familiarize yourself with the parts. Locate the numbers on the lenses. What
magnification is written on each of them?
Ocular Lens
Scanning Objective
Low Power Objective
High Power Objective
2. The total magnification is determined by multiplying the objective lens with the ocular lens.
What is the total magnification if you are using the Scanning objective? _______
Low power objective? _______
High power objective _______
3. Examine the diaphragm with the microscope on. As you turn
the wheel, the viewing field should become lighter or darker.
Gently and carefully tilt the microscope to view the diaphragm from
underneath. Sketch what the diaphragm looks like from
underneath 

Which number on the diaphragm dial provides the
most light? ___________
4. Look into the eyepiece, turn it left and then right. There may be a line inside that moves as you twist, this is the
pointer. (If you don’t have one, find someone that does have one.) What do you think the purpose of this line
is? ________________________________________________________________________________________
Measuring with a Microscope
1. Use a clear ruler to determine the width of the viewing field under the low power objective
(10X). Position the ruler so that the millimeter marks are visible in your viewing field. Remember
that there are 1000 micrometers in a millimeter.

Estimate the length (diameter) of your viewing field in micrometers
_____________________
You cannot use this method to determine the diameter under high power (try switching
objectives). Instead you can use a mathematical proportion method to determine the diameter
under high power. High power field diameter = low power field diameter x low power
magnification / high power magnification

What is the diameter (in micrometers) of your high power field
____________________
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
Fill out the table below after viewing prepared specimens.
Name of Object
Measurement of Object
_________________________________________________________________________________________
Making a Wet Mount of a Slide- Prepare a slide of the “letter e” following
these instructions.
1. Cut a letter “e” from newsprint. Have a dissection kit and use its tools.
2. Gather a thin slice/piece of whatever your specimen is (the letter e). If your specimen is too thick,
then the coverslip will wobble on top of the sample like a see-saw:
3. Place the specimen (the letter e) in the center of the glass slide. Place ONE drop of water
directly over the specimen on the glass slide. If you put too much water over the specimen, then
the coverslip will float on top of the water, making it harder to draw the specimens as they float
past the field of view!
4. Place the coverslip at a 45 degree angle (approximately), with one edge touching the water drop,
and let go.
5. Place the slide (Letter E) on the microscope so that the letter is over the hole in the stage
and is right side-up. Check the diaphragm setting, it should be at 1. Click the scanning
objective (the smallest one) into place and use the coarse adjustment knob (the largest one) to
focus the slide. If you cannot get a focus at this point, ask your teacher for help.
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a. Use the scanning objective to view the letter and use the coarse knob to focus.
b. Switch to the low power objective – you may need to adjust the course knob a bit.
c. Finally, switch to high power. Remember at this point, you should only use the FINE adjustment
knob.
Draw the “e” as it appears at each magnification. Drawings should be drawn to scale
and you should note the orientation of the e in the viewing field (is it upside down or
right side up?)
SCANNING
LOW
HIGH
6. Switch back to the scanning or low objective, and then push the slide to the
left while you view it through the lens. Which direction does the “e” appear to
move to you? _________________________
_________________________________________________________________
Common Things -- choose 2 specimens from the box of “common things”. Draw each specimen under
scanning and low power. Use the label on the slide to name each. You can view them under high power, but you
only need to sketch them at scanning and low.
Specimen 1 Name ___________________________
Scanning
Low Power
Specimen 2 Name ___________________________
Scanning
Low Power
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Depth Perception
1. Make a wet mount slide with three different colored threads on it. Write down the order of colors from bottom to
top:
 bottom= __________________________
 middle=____________________________
 top=_______________________________
View the slide under scanning and then low power. You should note that you could only focus on one colored
thread at one time. Figure out which thread will be in focus by lowering your stage all the way, then slowly
raising it until the thread comes into focus. The first thread to come into focus is the answer below:

Which color thread is in focus? ______________________________
Knowledge Base
1. Answer true or false to each of the statements
a. __________ on high power, you should use the coarse adjustment knob.
b. __________ the diaphragm determines how much light shines on the specimen.
c. __________ the low power objective has a greater magnification than the scanning objective.
d. __________ the fine focus knob moves the stage up and down.
e. __________ Images viewed in the microscope will appear upside down.
f. __________ if a slide is thick, only parts of the specimen may come into focus.
g. __________ the type of microscope you are using is a scanning microscope.
h. __________ for viewing, microscope slides should be placed on the objective.
I. __________ In order to switch from low to high power, you must rotate the revolving nosepiece.
j. __________ the total magnification of a microscope is determined by adding the ocular lens power to the
objective lens power.
k. _________ the pointer is used to position slides on the stage.
l. __________ the first step in viewing specimens is to use the scanning objective.
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