The Compound Light Microscope

1
The Compound Light Microscope

• Section 1-4

2
What is a compound light microscope?

• Mechanism for enlarging
• an image

3
How Does a Microscope Work?
the specimen
the image
the eye
Each lens magnifies the image, increasing its
overall size
A lens is a bi-convex disk that bends light
The bent rays produces an image
The farther the light rays are bent, the
larger the image appears
4
Evolution of the microscope
Choice of lens magnification
2 set lenses
5
How Does a Microscope Work?
the specimen
the image
the eye
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!
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Resolution vs. Magnification
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How Does a Microscope Work?
the specimen
the image
the eye
The image is always seen upside down and
backwards from its actual position
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Magnification

• 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

400
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The Parts of the Microscope and Their Function
Magnification
Maintains proper distance between lenses
Hold objectives- rotates to change magnification
Support body tube
Magnification
Supports slide
Holds slide In place
Focuses image
Regulates amount of light
Sharpens the image
Reflects light towards eyepiece
Supports microscope
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Proper Procedures

• Carry the microscope with one hand under the base
  while grasping the arm with the other hand
• Place microscope 5 inches from the edge of the
  table
• Be careful of the cord when moving around the lab
  tables!!

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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!

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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!
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Storing the Microscope
Four steps prepare the microscope for storage

• the 10X objective is in place
• the stage is all the way down
• the power is off
• the cord is wrapped around the base

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Lets Review!
Eyepiece
Body tube
Nosepiece
Arm
Low power
Medium power
Stage
High power
12.
Course adjustment
Stage clips
Diaphragm
13.
Fine adjustment
Light source
Base
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Microscope Self Quiz
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So Lets Review
Lets Review!
Eyepiece
Body tube
Nosepiece
Arm
Low power
Medium power
Stage
High power
Stage clips
Course adjustment
Diaphragm
Fine adjustment
Light source
Base