Microscope Lab Objectives
 Identify the parts of dissecting and compound light
microscope and give their functions.
 Coordinate their use to accurately focus on materials
provided at the levels of magnification indicated on your
response sheet without damaging the microscope or slides.
 Demonstrate proper procedures for cleaning and preparing
microscopes for use and returning them to their assigned
storage place in proper condition.
Common Microscope Types
Dissecting
Compound
Electron
Binocular
microscope
Microscope Type Uses
Dissecting microscope :
Allows one to study the entire object in three dimensions. (Examples: insects
and leaves)
The compound light microscope :
Uses light rays which are magnified and focused by means of lenses. This type
is used to examine tiny or thinly sliced cross sections.
Electron microscopes :
Uses a beam of electrons which are magnified on a photographic plate by means
of an electromagnetic lens.
Compound Light Microscope Parts &
Functions
Eyepiece:




Magnifies material being
viewed by 10X
The part of the microscope
you look into
Sometimes contains a
pointer that can be seen as
you look into the eyepiece.
May also be called the
ocular.
Microscope Parts & Functions
Nose piece:

Part of microscope to
which the objectives are
attached

Rotates to allow for the
changing of objectives
to increase or decrease
magnification.
Microscope Parts & Functions
Arm:



Part of microscope to
which the nosepiece is
attached
A secure part of the
microscope to hold on to
when the microscope is
being carried.
Sometimes includes a
cord hanger for power
cord storage
Microscope Parts & Functions
Objectives:


Magnify material
being examined
Scanning


10X


magnifies 10X
High dry


magnifies 4X
magnifies 40X
Oil immersion

magnifies 100X
Total magnification = magnifying power of eyepiece
x
The magnifying power of the objective in use.
Microscope Parts & Functions
Stage:
 Platform on which
microscope slide rests
Mechanical Stage:

Used for adjusting the
position of the slide for
viewing
Slide holder:

Secures slide to the
mechanical stage
Mechanical Stage
control knobs:

Move the slide
Microscope Parts & Functions
Coarse adjustment
knob:

Coarse focusing
Fine adjustment
knob:
 Precise focusing
Microscope Parts & Functions
Substage condenser

concentrates light & directs it
through opening in microscope
stage
Iris diaphragm:

regulates the amount of light
passing through the substage
condenser

increases resolving power of the
microscope
Microscope Parts & Functions
Iris diaphragm lever:
 adjusts the iris
diaphragm to increase
or decrease microscope
resolution
Condenser control knob:
 raises & lowers condenser
Microscope Parts & Functions
Illuminator

Light source
Illuminator control:


Controls the intensity of
light
Serves as the on/off switch
for some microscopes
Base:
o provides support for
microscope
Microscope Storage
Microscope Cabinet
Individual Storage
Microscope Storage
Always with a dust cover
Microscope Transport
Always with one hand on the arm & one on the base.
Preparation for Storage
Clean microscope
Rotate shortest objective
(4X) into place over stage
Lower stage for max
distance between
objective & stage
Wrap cord around base
or on cord hanger
Preparation for Storage
Adjust mechanical
stage so nothing sticks
out from the sides
Replace dust cover
Return microscope to
storage area
Preparation for Use
Transport microscope
to work station
Remove dust cover
Plug in microscope
Inspect and clean
microscope
Microscope Cleaning
Use only lens paper to
clean glass parts of
microscope.
Use glass cleaner with
lens paper to remove
immersion oil from
objectives, etc.
Kimwipes or paper towels may only be used
to clean microscope slides & non-glass
parts of the microscope.
Prepare a wet mount using letter "e" from a
newspaper.
1. Obtain letter e and place it on a clean dry slide.
2. Add a drop of water and cover with a cover slip by holding the
cover slip at a 45o angle to the drop of water with one edge of the
coverslip on the slide. Then gently and slowly lower the coverslip
over the drop to get rid of air bubbles.
3. Place your slide on the stage, and hold the slide in place by the
clips. Be sure to have
opening of the stage.
the
structure
to
be
examined
over
the
Prepare a wet mount using letter "e" from a
newspaper.
4. Observe under the ocular and focus using the coarse adjustment
knob until he image "e" is clear. Always begin your examination
with the lowest power objective lens (4X). Make sure that the lens
does not touch the slide.
5.
Once
the
structure
is
seen
it
may
be
necessary
to
adjust
the
amount of light by rotating the diaphragm slightly so that you get
maximum illumination. Also, adjust the condenser.
6.
Use the fine adjustment knob to sharpen the focus if needed.
7.
When
open.
looking
through
the
eyepiece,
practice
having
both
eyes
Total magnification of 40x
Total magnification of
100x
Draw what the “e” looks like at
the longest objective
WHAT IS THE TOTAL MAGNIFICATION?
Viewing for depth of field
Notice the textural details visible
in the yellow thread.
Both the red and blue threads
are out of focus.
To determine the relative position of
all 3 colored threads, you must raise
and lower your objective lens slowly
(known as "focusing up and down")
observe the order in which the
threads go in and out of focus.
As your objective lens approaches
the slide, the first thread to come
into focus is on the top.
Whitefish blastocyst
Whitefish blastocyst
Whitefish blastocyst
Whitefish blastocyst
Onion root tip
Onion root tip
Multicellular organisms
Human Epithelial Cells (400X)