Microscope Lab Activity
Materials
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Compound microscope
Ruler slide
Clean slide
Cover slip
Pipette
Procedure
Part I Microscope Handling
1. Carry the microscope with both hands --- one on the arm and the other under the base of the microscope.
2. Examine the microscope and quiz your lab partner on the function of each of the parts listed on the
right side of the diagram.
1. eyepiece or ocular
2. body tube
3. fine adjustment knob
4. nosepiece
5. high power objective
6. low power objective
7. diaphragm
8. mirror/light
9. base
10. coarse adjustment knob
11. arm
12. stage clip
13. inclination joint
14. stage
Part II Determining Total Magnification
1.
Locate the numbers on the eyepiece and the low power objective and fill in the blanks below.
Eyepiece magnification
______________
2.
(X)
Objective magnification
______________
=
Total Magnification
_____________X
Do the same for the medium and high power objectives.
Eyepiece magnification
______________
(X)
Objective magnification
______________
=
Total Magnification
_____________X
Eyepiece magnification
______________
(X)
Objective magnification
______________
=
Total Magnification
_____________X
Part III Observing the Letter “e”
1. Obtain a letter “e” slide.
2. Move the letter “e” slide left and right and up and down.
3. In which direction does it move under the microscope, relative to the direction you move it with your
hands?
4. Looking at the letter “e” slide on the stage, which way up is the “e”?
5. Explain the general rule about the way things appear under your microscope, relative to their actual
position.
Part IV Calculating Field of View
1. Obtain a ruler slide.
2. Center the slide on the microscope stage so that the millimeter marks go across the widest part of the
viewing circle (called the field of view).
3. Adjust the microscope to its lowest magnification. What magnification is this? (Remember that
magnification is the product you get by multiplying the powers of the eyepiece, or ocular, lens and the
objective lens; magnification is written with an X that means times.)
4. Look through the eyepiece and adjust the focus until you can see the ruler clearly.
5. Count the number of millimeter lines you can see across the widest part of the field of view.
6. Record your answer in the following format: The diameter of the field of view = ____ mm at ____X
magnification.
7. Now change the magnification. If you worked carefully, you should still be able to see the ruler. (If not,
back up to the lower magnification and make the necessary adjustments.)
8. How many millimeter lines can you see now?
9. Record your answer in the following format: The diameter of the field of view = ____mm at ____X
magnification.
10. Repeat this process for each magnification power of your microscope.
11. What happens to the size of the measuring lines?
12. How might this affect the accuracy of your measurements at a particular magnification?
Part V Preparing a wet mount of your hair
1.
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4.
Obtain a piece of hair.
Place it on the glass slide and add a drop of water.
Place the cover slip on the drop of water at a 45o angle and slowly lower it onto the slide.
Turn on the microscope and place the slide on the stage; making sure the hair is facing in the field of view.
Using the course focus and low power, move the body tube down until the hair can be seen clearly. Draw
what you see in the space below.
5. Turn off the microscope and wind up the wire so it resembles its original position.
6. Place the low power objective in place and raise the body tube.
7. Place the scope back in its original space in the cabinet.
http://www.ekcsk12.org/science/lelab/microscopeuselab.htm
Conclusion
Answer the following questions in the space provided:
1. State 2 procedures that should be used to properly handle a light microscope.
2. Explain why the light microscope is also called the compound microscope.
3. Explain what it means when we say that images observed under the light microscope are reversed and inverted.
4. Explain why the specimen must be centered in the field of view on low power before going to high power.
5. A microscope has a 20 X ocular (eyepiece) and two objectives of 10 X and 43 X respectively:
a) Calculate the low power magnification of this microscope. Show your formula and all work.
b) Calculate the high power magnification of this microscope. Show your formula and all work.
6. In three steps using complete sentences, describe how to make a proper wet mount.
1.
2.
3.
7. Describe the changes in the field of view and the amount of available
light when going from low to high power using the compound microscope.
8. How does the procedure for using the microscope differ under high power as opposed to low power?
http://www.ekcsk12.org/science/lelab/microscopeuselab.htm