Honors Biology
Advanced Microscope Lab (23 pts)
Name:___________________ Period:___
Using the Microscope and Slide Preparation
Directions: Read each section and follow each set of steps below. Be sure to follow all directions and answer each
question and perform each task. You will be expected to know how to use the microscope and understand how each part
functions. If you are unsure please ask for help.
Directions for Drawing Specimens:
1. Use pencil - you can erase and shade areas
2. All drawings should include clear and proper labels (and be large enough to view details). Drawings should be
labeled with the specimen name and magnification.
3. Labels should be written on the outside of the circle. The circle indicates the viewing field as seen through the
eyepiece, specimens should be drawn to scale - i.e......if your specimen takes up the whole viewing field, make
sure your drawing reflects that.
A. Magnification
A. The magnification written on the ocular lens (eyepiece) is _____________
B. The magnification on the Scanning objective _______ Low Power _______ High Power _______
C. What is the total magnification for each lens? (multiply ocular x the objective) (3
pts)
Scanning ____________ Low Power ______________ High Power _______________
B. Diaphragm
Examine the diaphragm, determine how to change the amount of light that passes through
your viewing field. Diaphragms on microscopes can be different depending on the model.
Describe how the diaphragm works: (1 pt)
C. Depth perception
Obtain a slide with three different colored threads on it. 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 is on top 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 one
on top.
1. Which color thread is on top? _____________
2. Which color thread is in the middle? _____________
3. Which color thread is on the bottom? ______________ (1 pt)
D. Making a Wet Mount of a Slide
1. Cut out a lowercase letter “e” from your paper and put it on your slide.
2. Place ONE drop of water directly over the specimen.
3. Place the coverslip at about a 45-degree angle with one edge touching the water drop and then gently let
go. Performed correctly the coverslip will perfectly fall over the specimen and will not have air bubbles
4. Focus the slide first with the scanning objective using the coarse, then fine adjustment knobs and draw.
5. Rotate the nosepiece to low power and focus again.
6. Finally, focus the slide under high power.
NOTE: Remember, at low and high power, you should ONLY use the fine adjustment knob.
**Draw the letter e exactly as it appears in your viewing field for each magnification. The circles below represent
your viewing field. The e should take up as much space in the drawing as it does in your viewing field while you're
looking at it.
1. (½ pt) Does the lens of the microscope reverse the image? _________
2. (½ pt) Does it flip the image? (upside down) _________
3. Have your partner push the slide to the left while you view it through the lens.
a. (1 pt) Which direction does the e appear to move? __________________
E. Investigation of Pond Water & Microorganisms
1. Prepare a wet mount of pond water - a sample of pond water is provided in a jar. The best specimens
usually come from the bottom and probably will contain chunks of algae or other debris that you can see
with your naked eye. (Be careful that your slide isn’t too thick)
2. Use the microscope to focus on the slide - try different objectives, some may be better than others for
viewing the slide. Adjusting the diaphragm may also help see small swimming organisms in the water.
3. Use the identification page to help you identify 3 specimens. Draw your specimens below and label with the
NAME of the specimen and the MAGNIFICATION. (3 pts)
F. Investigation of Large Specimen
Light microscopes are only useful for viewing small thin specimens. Stereoscopes present a larger field of viewing
and handle depth much better than the light microscope. The drawback of the stereoscope is that it does not have
a high magnification. Examine one of the stereoscopes in the room. They will be positioned around the room with
specimens.
Name/Description of specimen(s) viewed: _________________________________________________________
What are the magnifications of the stereoscope? ____________ Can you change the type of light? ________ (1 pt)
Draw the specimen as it is seen under magnification:
G. Measuring with a Microscope
1. Use a ruler to determine the width of the viewing field under the scanning objective. Position the ruler so
that the millimeter marks are visible in your viewing field. Remember that there are 1000 micrometers in a
millimeter.
2. Estimate the diameter of your viewing field in micrometers: scanning _______ low power ________
3. You cannot use this method to determine the diameter under high power (try switching objectives, you
won't be able to even see the ruler). Instead you can use a mathematical proportion method to determine
the diameter under high power. Show your work below with your estimate of the length (in micrometers) of
your high power field of view.
High Power Field of View (µ)
Low Power Field of View (µ)
Low Power Magnification
High Power Magnification
High Power Field of View = _________ (1 pt)
4. Sketch a cork slide accurately, drawing it to scale, with attention to detail.
Make sure to label the magnification. (1 pt)
Length & Width of Cork = ____________ (1 pt)
Research the size of the average cork cell. Do your data and your
calculations make sense? _________
H. Answer true or false to each of the statements (½ pt each)
__________ On high power, you should use the coarse adjustment knob.
__________ The diaphragm determines how much light shines on the specimen.
__________ The low power objective has a greater magnification than the scanning objective.
__________ The fine focus knob visibly moves the stage up and down.
__________ Images viewed in the microscope will appear upside down.
__________ If a slide is thick, only parts of the specimen may come into focus.
__________ The type of microscope you are using is a scanning microscope.
__________ For viewing, microscope slides should be placed on the objective.
__________ In order to switch from low to high power, you must rotate the revolving nosepiece.
__________ The total magnification of a microscope is determined by adding the ocular lens power to the
objective lens power.