BIOLOGY LABORATORY
USE OF THE MICROSCOPE
Lab Book
• First page, front and back will
be Table of Contents
• Number every page starting
with the second full page
Lab reports
• Title centered on the first line of the page
• Introduction on the second line at the left
margin
• Hypothesis: at the end of the introduction
• Procedure at the left margin, numbered
steps
• Data at the left margin should include
tables and charts
• Analysis at the left margin written in
paragraph form in complete sentences
• Conclusion at the left margin (if applicable)
• Date at the end of each lab
BACKGROUND
INFORMATION
• The microscope is a tool used often by
biologists. Like any other instrument, using it
correctly requires some practice.
• Microscopes can also be used to measure
objects.
• Most microscopes are parfocal. This means
that only slight adjustments are needed to
bring an object into focus when objective
lenses are rotated.
• Adjusting the light using the diaphragm under
the stage allows you to see the object you
are viewing more clearly.
• The capability of the lens system to
show fine detail is the resolution. At
high resolution parts of the object
are clear and distinguishable.
• The distance from the ocular lens at
which the light coming through it
focuses is called the eye relief.
• In this lab you will learn how to
effectively manipulate the
microscope and how to determine
the size of the objects viewed with
the microscope.
INTRODUCTION
• In your introduction in your lab
book, explain what the various
parts of the microscope are and
what they are used for.
PROCEDURE
• 1. Make a wet mount using two different
colored threads. Cross the threads in an X,
positioning the slide so that the center of the
X is in the center of the low power field.
• 2. Determine if the microscope you are using
is parfocal. Record your results.
• 3. Using low power, adjust the light until you
can see the threads clearly. Draw one of the
threads in your lab book.
• 4. Using the fine adjustment, determine which
color thread is on top. Record your results.
(Is that how you placed them on the slide?)
•
• 5. Under low power use the fine
adjustment to bring the thread into focus.
Rest a small piece of notebook paper flat
against the ocular. Raise the paper slowly.
Move the paper up and down until you see
a small, sharply defined disk of light.
Measure and record the eye relief of the
ocular. Record your results.
• 6. Cut out a lower case letter e from the
newspaper and make a wet mount.
• 7. Using low power adjust the microscope
until you can see the letter clearly.
• 8. Move the letter to the left. Record the
movement you see when you are looking
through the eyepiece. Continue to move
the letter to the right, up and down.
Copy this template on the last page of your lab book.
title
Slide section:
Magnification:
Description:
DATA
• In your lab book label a section
Data.
• 3. Drawing of thread:(new page)
• 2. The microscope (is, is not)
parfocal
• 4. ________ color thread is on top.
That (is, is not) how I placed them
on the slide.
• 5. The eye relief of the ocular is:
• 8. Record how these movements
and how they appear when you are
looking through the eyepiece.
ANALYSIS
• In your lab book label a section
Analysis and, in paragraph form,
answer the following questions.
•
Explain why it is important
for you to know the eye relief of
your microscope.
•
Explain how you adjust the
resolution of a microscope.
Calculations
• Calculate the area of the low and
high power fields. (millimeters and
micrometers)
• Diameter of high power field =
0.75mm
• Diameter of low power field =
1.50mm
• Area of circle = Π r2
• 1 millimeter = 1000 micrometers ( µ)