MICROSCOPE LAB
Name:__________________________________
Date:____________________Hour:__________
Objective: When you complete this lab, you should be able to:
 Demonstrate proper care and use of a compound microscope.
 Identify the parts of the microscope and describe the function of each part.
 Compare magnification, resolving power and contrast.
 Demonstrate inversion and depth of field
 Use the microscope as an instrument of measure
Introduction:
The unaided eye can detect objects as small as 0.1 mm in diameter. Most cells are between 0.01 and 0.1 mm in
diameter and cannot be seen without a microscope. A microscope contains one or more lenses and is designed to view
detail that cannot be seen with the unaided eye. The light microscope, using a lens system, extends our vision a
thousand times so that an object as small as 0.1µm (micrometer) in diameter can be seen. A lens functions by refracting
(bending) light rays coming from an object and focusing them to form an image of that object. A magnifying glass is a
simple light microscope. A microscope consists of a set of lenses that focus an enlarged image of an object.
PRE-LAB:
Part 1: Purpose of the Microscope
The microscope is useful in collecting data and making observation in scientific experiments. Microscopy involves three
basic concepts:
Magnification
The degree to which the image of the specimen is enlarged
Resolving Power
How well the specimen detail is preserved in the magnifying process
Contrast
The ability to see specimen detail against its background. Stains and dyes are often used
to increase contrast.
The microscope is a very expensive and fragile
tool used in science. The proper way to carry it
is with one hand on the arm and one hand on
the base.
.
Part 2: Microscope Parts: Label the names of the parts, based on the functions given below.
WORD BANK: stage opening, base, fine focus, light source, arm, objectives, revolving nosepiece, eyepiece, coarse focus,
diaphragm, stage, body tube, stage clips
Name of Part
Function of Part
Supports body tube and stage of microscope
Part of microscope that you look through (usually 10x magnification)
Platform where slide is placed for viewing
Holds slide in place on stage
The hole in the stage that allows light to pass through to the
specimen
Bottom of microscope, supports microscope
Holds eyepiece lens and objective lens at the correct distance for
magnification
Holds objective lenses
Provides light to view specimen
Regulates amount of light allowed to pass through stage opening
Larger knob used to move the stage a large distance, used for
beginning focusing of specimens on lowest objective lens
Smaller knob, used for fine focusing of specimens
Used to view specimens at different magnification (scanning lens =
4x, low power = 10 x, high power = 40x, oil immersion lens (on some
microscopes only)= 100x)
A. Match the microscope part with the correct letter from the diagrams below.
________Arm
________Body Tube
________Stage
________Fine Focus Knob
________Light Source
________Eyepiece
________Objective
________Coarse Focus Knob
________Stage Clip
________Stage Opening
________Diaphragm
________Base
________Revolving Nosepiece
LAB:Part 3: Focusing the Microscope—Make sure you AND your partner(s) can complete all of the following steps.
A. Slide #1
4X Power
1. Obtain a prepared slide. Identify the slide
label:_____________________________________
2. Make sure the scanning (lowest—4X) power lens is in place.
3. Lower the stage so there is enough room to place the slide on the
stage so that the lens is not hitting the slide.
4. Place the slide on the stage, and hold it in place with the stage clips.
Move the slide so the specimen is over the stage opening.
5. Looking at the side of the microscope, raise the stage (using the
coarse focus knob) as far up as it goes, but do so slowly so as not to
hit the slide hard.
10X Power
6. Looking through the eyepiece, move the coarse focus until the
specimen comes into focus. Adjust the fine focus knob until the
specimen is clear.
7. Adjust the diaphragm if needed to adjust amount of light.
8. Draw what you see under the lowest power to the side.
9. With the slide still in place and centered, change the objective to
the 10X power lens.
10. Do NOT adjust the coarse focus knob on this power. Use only the
fine focus to bring the specimen in focus.
11. Draw what you see under this power.
12. With the slide still in place and centered, change the objective to
the 40X power lens.
13. Do NOT adjust the coarse focus knob on this power. Use only the
fine focus to bring the specimen in focus.
14. Draw what you see under this power.
40X Power
Part 4: Specimen Orientation
1. Obtain a prepared slide of the letter “e.”
2. Place the letter “e” on the stage and starting with the lowest (4X)
power objective, focus and center it on the stage.
3. Draw the letter “e” as you see it on the lowest (4X) power.
Questions about Part 4:
1. With the lowest power objective in place, move the slide to the right while watching the image through the
microscope. In which direction do you see the image move? ______________________________________
2. Move the slide away from you while watching the image through the microscope. In which direction do you see
the image move? __________________________________________
3. What is the relationship between the movement of the object and the movement of the image?
___________________________________________________________________________________________
POST-LAB QUESTIONS:
1. Describe how a microscope should be properly held and carried. _______________________________________
_______________________________________________________________________________________________
2. How is the total magnification of a microscope determined? __________________________________________
_______________________________________________________________________________________________
3. If the magnification of the eyepiece is 10x, and the magnification of the objective you are using to view is 7x,
what is the total magnification you are viewing the specimen under? __________________________________
4. Do you see more or less area in your field of view when under high power compared to low power?
_________________ Explain why. __________________________________________________________________
_______________________________________________________________________________________________