How to Use the Compound Microscope
OJECTIVES
1. Prepare the compound microscope for examining specimens.
2. Locate the specimen of interest and focus it under the LPO and HPO.
MATERIALS
compound microscope
lens paper
scissors or cutter
letter e (cut from a magazine or news paper)
glass slide
medicine dropper
water
coverslip
ruler
hair strand with follicle
PROCEDURE
Note: Before you start this activity, familiarize yourself with the parts of a
compound microscope and with the function of its parts.
To view the image of the specimen clearly, the following steps must be strictly
followed.
1. Place the microscope in front of you but far enough from the edge of the table
for you to look through it with ease. The arm should be toward you.
2. Gently clean all optical surfaces with the lens paper and not with the regular
tissue paper.
3. Cut a small letter e from a newspaper or magazine and place it on the center
of the glass slide. Use a medicine dropper to drop a small amount of water
over it and cover with a cover slip.
4. Put the slide at the center of the stage and secure it with the stage clip.
5. Click the LPO in place and lower the objective as close as possible to the
slide using the coarse adjustment knob, and then the fine adjustment knob.
Always begin your examination with the LPO. The HPO is longer than the
LPO and can break and damage the slide if used incorrectly.
6. Keeping both eyes open, focus the specimen carefully using the coarse
adjustment knob. You do not see anything with your eyes open , cover one
eye with your palm. Sharpen the focus with one eye.
7. Using the iris diaphragm, adjust the amount of light that illuminates the
specimen. This is important since with too much light you cannot see clearly
the details of the specimen under investigation.
8. Once the specimen is focused, move the slide slightly to the left and then to
the right and note the orientation of the specimen, whether upright or inverted
What is the position of your letter e specimen?
9. This time click the HPO in place, focus the specimen using the fine
adjustment knob. Observe. Replace the letter e specimen with a 1 cm piece
of hair strand with follicle. Focus the hair follicle under LPO, then HPO. Take
note of its size.
10. Compare the appearance of the follicle under LPO and its appearance under
HPO.
11. Once you are through, clean the objectives and the oculars. Make sure that
the stage is dry before returning the microscope into its storage box or
cabinet.
12. Draw letter e as seen under LPO and HPO. Draw the hair follicle as seen
under the LPO and HPO.
13. Answer the questions in Data and Results.
DATA and RESULTS
A.
Letter e as seen under LPO
Letter e as seen under HPO
B.
Hair follicle as seen under LPO
Hair follicle as seen under HPO
C. Questions
1. Letter e.
a. What is the position of letter e when you moved the slide to the left? To
the right?
b. In what objective did you see the whole mount of the letter e.?
2. Hair follicle
a. Did you see the whole specimen?
b. What happened to the image of the hair follicle when focused under
LPO? HPO?
ANALYSIS AND INTERPRETATION
1. Why must you use the fine adjustment knob in focusing the specimen under
HPO?
2. Why should you put the specimen at the center of the field of view before
changing the objective?
GENERALIZATION
APPLICATION
1. If an ocular can magnify an object 10x, and the objective 100x, what is the
total magnification of the specimen being examined under the microscope?
2. What are some of the possible reasons why a specimen could not be focused
clearly under the microscope?