Microscope Notes

1
Microscope Notes

• The proper use of microscopes is important in
  your study of biology.
• In the class you will find two different types of
  microscopes, a compound (high power) microscope
  and a dissection or stereo (low power microscope)

Low power dissection microscope
High power compound microscope
2
Microscope Parts

• High power microscopes have two lenses which
  provide the magnification. The first lens is
  located in the eyepiece and is 10X. The second
  lens is found on the revolving nosepiece and
  contains a 4X, 10X, or 40X objective lens. Total
  magnification is equal to the eyepiece x the
  objective lens selected.

3
Microscope Use

• To use the microscope place a glass slide on the
  stage of the microscope, and turn the revolving
  nosepiece until the low power (4X) objective is
  in line with the eyepiece.
• Use the coarse adjusting knob to turn the
  objective lens close to the stage.
• Slowly move the coarse adjusting know until the
  specimen becomes focused.
• Once your specimen is found on low power you can
  move the objective to 10X for more magnification,
  and then 40X.

4
Microscope Use

• When your objective lens is on high power you
  only use the fine adjusting knob to focus.
• Stage clips may or may not be used to hold your
  slide on the stage.
• The diaphragm allows you to adjust the light
  allowed onto the stage.

5
Microscope Care

• When done using a microscope move the objective
  lens to low power and place the cover over the
  microscope.
• If you move a microscope use both hands and be
  careful.
• Make sure to unplug your microscope when done.
• Use lens paper to clean off dust from a slide of
  microscope lens.

6
Preparing Slides

• Usually a specimen is placed on a glass slide,
  and sometimes a cover slip is placed over the
  specimen.
• Rarely would you ever put a specimen directly on
  the stage of a microscope.
• A wet mount involves placing a specimen on a
  slide, adding a drop of liquid, and then using a
  cover slip over the top.

7
Using the Microscope to Measure

• Microscopes allow you to view things too small to
  be seen with the naked eye.
• Using microscopes you can observe, measure, and
  study small structures and organisms.
• To measure with a microscope you need to use a
  ruler to find the (mm) of your field of view on
  low power.

Field of view
8
Measuring with a Microscope

• When you know the diameter of your field of view
  on low power you convert these millimeters to
  micrometers. To do this you move the decimal
  three places to the right. There are 1000
  micrometers in 1 millimeter.
• Ex. 4 mm 4000 micrometers
• To find your field of view on medium power you
  take your low power field of view and divide it
  by 2.8.
• To find your field of view on high power you take
  your medium power diameter and divide by 4
• In my example 4000/2.8 1428 micrometers on
  medium
• 1428/4 357
  micrometers on high power

9
Measuring with a Microscope

• To measure with a microscope you estimate based
  upon knowing your field of view.
• What is the length of the specimen shown in the
  field of view to the right?

Field of view 500 micrometers
10
Measuring Practice
Field of view 500 micrometers
Field of view 1000 micrometers
Width of specimen ______ Length of specimen
_____
Diameter of specimen ______
Area of specimen ______