2. What is a compound
light microscope?
• Mechanism for enlarging
an image
3. Evolution of the microscope
2 set lenses
Choice of lens
magnification
4. How Does a Microscope Work?
the eye
the image
the specimen
Each lens magnifies the
image, increasing its
overall size
A lens is a bi-convex disk that bends light
The farther the light rays are bent, the larger
the image appears
The bent rays produces an image
5. How Does a Microscope Work?
the eye
the image
the specimen
As the light rays are spread farther
apart, the clarity or resolution of
the image decreases
Resolving power: A measure of the ability of a
lens or optical system to form separate and
distinct images of two objects with small
angular separation.
Light microscopes are limited in their
magnification by their resolving power!
7. How Does a Microscope Work?
the eye
the image
the specimen
The image is always seen upside down
and backwards from its actual position
8. • The two lenses are called:
– Eyepiece
– Objective
• The eyepiece has a magnification of “10x”
• The magnification of the objective lenses
vary and are marked on the lens
• Total magnification =
(Eyepiece) X (Objective)
• Example:
10 X 40 =
Magnification
400
9. Types of Microscopes:
1. Compound Light Microscope (what we use most
often)
2. Stereoscopes – also known as dissecting scopes
3. Electron Microscopes
17. The Parts of the Microscope and Their
Function
Magnification
Support body tube
Supports slide
Focuses image
Sharpens the image
Supports microscope
Reflects light
towards eyepiece
Regulates
amount of light
Holds slide
In place
Hold objectives-
rotates to change
magnification
Magnification
Maintains
proper distance
between lenses
18. Proper Procedures
1. Carry the microscope
with one hand under the
base while grasping the
arm with the other hand
2. Place microscope ~5
inches from the edge of
the table
Be careful of the cord
when moving around
the lab tables!!
19. Proper Procedures
5. Place slide on stage,
center specimen over
stage
6. Locate specimen on
low power using coarse
adjustment
7. Carefully switch to
medium or high power
8. Focus image with fine
adjustment
Avoid damaging slide!
Do not use course adjustment with high power!
20. Proper Procedures
3. Rotate the nosepiece
to obtain the proper
objective lens
Make sure the lens
clicks into place!!
4. Look through the
eyepiece and switch
on the lamp
This is your field of
view!
21. Storing the Microscope
1. the 10X objective is
in place
2. the stage is all the
way down
3. the power is off
4. the cord is wrapped
around the base
Four steps prepare the microscope for storage:
