Name: _________________________________________
Period: __________
Date: ____________
CAN YOU SEE ME NOW?
Using the Compound Microscope
Microscope Care
1. Always carry the microscope with two hands.
2. Clean the microscope with LENS PAPER ONLY. Paper towel will scratch the lens.
3. Place the base of the microscope AWAY from the edge of the table; make sure the cord is not dangling and
in the way.
Using the Microscope
Before looking through the ocular, go through the following checklist:
1. Light is on
2. Rheostat is adjusted
3. Slide is on the stage
4. Scanning lens (4X objective) is in place
5. Specimen is centered – it must be over the hole in the stage so light passes through the specimen on the
Slide.
6. Start stage at the top position – UP
CHECKLIST FOR LOOKING THROUGH THE OCULAR
1. Adjust the oculars to your eyes
2. Coarse focus using the coarse adjustment knob
3. Adjust the iris diaphragm
4. Fine focus using the fine adjustment knob
5. Keep your specimen centered using the XY controls
DO NOT USE THE COARSE
ADJUSTMENT KNOB above 4X
objective or CRUNCH!
IMPORTANT TERMS:
Microscope Condenser Microscope Resolution
_______________________________________________________________________________
Iris diaphragm - ___________________________________________________________________________
Field of view - _____________________________________________________________________________
Prepared slide - ___________________________________________________________________________
Temporary wet mount slide - ________________________________________________________________
Depth of field - ____________________________________________________________________________
Parfocality - ______________________________________________________________________________
HOW TO CALCULATE TOTAL MAGNIFICATION
ocular (eyepiece) mag. X objective mag. = total mag. Example - 10x x 40x = 400x
IMPORTANT NOTE: The relationship between magnification and field of view and depth of field is inverse,
meaning that as one increases the other decreases, and vice versa. Therefore, increasing magnification
______________the width of the field of view. Increasing magnification also ____________the depth of field.
Procedure 1 – Making a wet mount slide
1. Clean a glass slide and cover slip with a paper towel. Hold by the edges to avoid smudging with
fingerprints.
2. Cut out a lower case letter "e" from a piece of newspaper. This "e" should be from the body of an article,
not from a headline!
3. Position the "e" on the center of a clean glass slide.
4. Use a dropper to place one drop of water on the cut piece of newspaper.
5. Place the cover slip at the edge of the drop of water at a 45-degree angle. Lower the cover slip slowly to
avoid air bubbles. There should be a continuous layer of water between the slide and the cover slip. You
may need to tap the cover slip gently to eliminate air bubbles.
6. Center the wet mount of the letter "e" on the stage with the "e" in its normal upright position. Note: Make
sure the bottom of the slide is dry before you place it on the stage. Turn the low power objective into
position and bring the letter "e" into focus. Draw the letter "e" as it is seen in the microscope.
7. Turn the 10X power objective into position and bring the letter "e" into focus. Draw the letter "e" as seen
through the microscope.
Drawing 4X (draw field of view)
Ocular magnification ___________
Objective magnification _________
Total magnification ____________
Drawing 10X (draw field of view)
Ocular magnification ___________
Objective magnification _________
Total magnification
ANALYSIS QUESTINS- restate the question and answer in complete sentences
In what ways is the image of the letter "e" different through the microscope as compared to looking at it
without the microscope? Name at least 2 ways:
1. _______________________________________________________________
2. ______________________________________________________________
3. What happened to the object and field of view when the magnification increased from 4X to 10x? Explain
why this happens using the relationship between magnification and field of view.
4. How did increasing to higher power (10X) affect the brightness of the image?
MOVEMENT OF IMAGES UNDER THE MICROSCOPE
1) Rotate the nosepiece until the low power objective clicks back into position and bring the letter "e" into
focus.
2) While looking through the eyepiece, move the slide in the directions indicated below and note the direction
the "e" appears to move: CHECK TWICE TO BE SURE OF THE DIRECTION
Moving the slide to the right makes the "e" appear to move ____________
Moving "
" " " left
"
" "
"
" " __________________
Moving the slide (clockwise) up makes the "e" appear to move _________________________
Moving "
" (counterclockwise) down makes " "
" " " ________________________
1. If you were tracking a microorganism that appeared to be moving from the right side of your field of view
to your left, which way would you move the slide to keep it in view? ________________________
2. If that same organism suddenly changed direction and started to move toward the bottom of your field of
view, which way would you move the slide to keep it in view? ___________________________
Procedure 2 – Depth of Field (review term)
Now make a wet mount slide of a piece of hair crossed over a thread. Focus and draw what you see on 4X, 10X
and 40X
Drawing 10X (draw field of view)
Ocular magnification ___________
Objective magnification _________
Total magnification ____________
Drawing 40X (draw field of view)
Ocular magnification ___________
Objective magnification _________
Total magnification
1. Can you get both fibers in focus at the same time at 10X and 40X? _________________
2. If the magnification were high enough, you wouldn’t be able to. Explain why using the term field of view.
Review the relationship between magnification and field of view from page 2 under Calculating
magnification.
Procedure 3 – Prepared slide
Choose one of the prepared slides and sketch the specimen. Follow Guidelines for Microscope Drawings
Title:
Ocular magnification _________
Objective magnification
Total magnification
__