Introduction to Microscopes!

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Introduction to Microscopes!

• Now Seeing IS Believing!

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A Brief History
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Simple Glass Magnifiers

• More than 500 years ago.
• In 1600s, this simple microscope allowed
  scientists to see cells and bacteria
• Problem not enough
  magnification

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First Compound Microscope

• Developed at the beginning of the 1600's, by the
  Janssen brothers and Galileo
• Problem images
  were blurred and
  had
  colored halos

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Simple Compound Microscope

• Invented in 1660s
• Problem all images had red or blue halos
  around them

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Even better!

• 1700 and 1800s great improvement in microscopes
• Usually made of brass (expensive)
• Had a tripod for support

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Modern Compound Microscope

• 1900s, started using iron
  instead of brass (cheaper)
• Only one eyepiece
  (monocular)
• Outside light source
  reflected onto mirror
• Very functional
• Still used today

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Fancy!

• Better images
• More magnification
• Better lighting
• Easier to use
• Now everyone, at one time or another, has looked
  through a microscope

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How Does It Work?

• A microscope works very much like a telescope.
• A telescope must gather light from a dim, far
  away object.
• So, it needs a large
  objective lens
  to
  gather as much light
  
  as possible and a
  
  long body to bring
  
  the image into focus.

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How Does It Work?

• Unlike a telescope, a microscope must gather
  light from a tiny specimen that is close-by.
• So the microscope does not need a large objective
  lens.
• Instead, the objective lens of a microscope is
  small.
• Then the image is again magnified by a second
  lens, called an eyepiece, as it is brought to
  your eye.

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Parts of a Compound Microscope
So EASY a KID could use it!
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Base

• The bottom of the microscope, used for support
• Hold this part with one hand when carrying a
  microscope

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Mirror

• Reflects the light so the specimen is easier to
  see

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Stage

• The flat platform where you place your slides. 
• It has a hole in it so light can shine through

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Clip

• Shiny clips on the top of the stage
• Holds a slide in place

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Arm

• Supports the tube and connects it to the base
• The part you hold when you carry the microscope

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Coarse Adjustment

• Large, round knob on the side of the microscope
• Either moves the stage or the top part of the
  microscope up and down

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Fine Adjustment

• Small, round knob on the side of the microscope
• Used to fine tune the focus after using the
  coarse adjustment knob.

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Eyepiece
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• The lens at the top that you look through.
• 10X power

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Body Tube

• The long tube that holds the eyepiece and
  connects the objective

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Nosepiece

• Rotating part of the microscope at the bottom of
  the body tube.
• It holds the objective lenses

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High Power Objective

• The longest objective lens
• The highest magnification
• 40X lens (40X x 10X 400X
  magnification)

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Low Power Objective

• The shortest objective lens
• The lowest magnification
• 4X lens (4X x 10X 40X
  magnification)

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Mid Power Objective

• The medium length objective lens
• The medium magnification
• 10X lens (10X x 10X 100X
  magnification)

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Diaphragm

• Controls the amount of light going through the
  hole in the stage

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Pop Quiz

• What two parts should you hold when you carry a
  microscope?
• Base Arm
• Where do you put a slide?
• On the Stage
• To focus, what knob do you turn first? Second?
• First, Coarse Adjustment
• Second, Fine Adjustment

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Test Your Skills . . .

• Arm
• Body Tube
• Stage
• Clip
• Base
• Coarse Adjustment
• Fine Adjustment

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Test Your Skills

• High Power Objective
• Low Power Objective
• Mirror
• Eyepiece
• Nosepiece
• Diaphragm

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• http//www.udel.edu/biology/ketcham/microscope/tes
  tFLV8.html
• http//www.wisc-online.com/objects/index_tj.asp?ob
  jIDBIO905