1. The Microscope Packet #4 11/12/2018 3:25:39 AM11/12/2018 3:25:39 AM
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2. Historical Timeline
1609 – Galileo Galilei develops a compound microscope with a convex and a concave les.
1665 – Robert Hooke publishes Micrographia and coins the word cell for structures he discovers in cork bark
1674 – Anton van Leeuwenhoek improves on a simple microscope for viewing biological specimens
1931 – Ernst Ruska starts to build the first electron microscope
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3. Types of Microscopes 11/12/2018 3:25:39 AM11/12/2018 3:25:39 AM
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4. Types of Microscopes I Compound Microscope
Light microscope that has two converging lens systems: the objective and the eyepiece
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5. Types of Microscopes II
Electron Microscope
Any class of microscopes that use electrons instead of light to form images of very small objects such as individual parts of small living things
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6. Types of Microscopes III
Transmission Electron Microscope
Microscope used to reveal the internal structure of microbial and cell types.
Scanning Electron Microscope
The electron beam is scanned, or swept over a metal coating to form a three-dimensional image.
Scanning Tunneling Microscope
Can produce three-dimensional images of individual molecule and atoms, as well as movies
Microscopes
Compound Microscope
Light Microscope
Electron Microscope
Transmission Electron Microscope
Internal Structures
Scanning Electron Microscope
3D image
Scanning Tunneling Microscope
Molecules & Atoms
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7. The Compound Microscope
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8. 11/12/2018 3:25:39 AM11/12/2018 3:25:39 AM © Ryan Barrow 2012

9. The Compound Microscope
Base
Supporting structure that generally contains the source
Condenser
Converges light beams to pass through the specimen
Iris Diaphragm
Controls the amount of light passing through the specimen
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10. Compound Microscope II
Objective Lens
Magnifies image
Body Tube (Arm)
Conveys light to the ocular lens
Ocular Lens (Eye piece)
Magnifies the image from the objective. A microscope with one ocular lens (eyepiece) is monocular; a microscope with two ocular lenses is binocular
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11. Compound Microscope III
Mechanical Stage
Allows precise control in moving the slide
Coarse Adjustment
Knob used to locate specimen
Fine Adjustment
Knob used to bring the specimen into sharp focus
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12. Compound Microscope IV
Total magnification
Calculated by multiplying the magnifying power of the objective lens by the magnifying power of the ocular lens. Increased magnification is no value unless good resolution can also be maintained.
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13. The Behavior of Light Used for the Compound Microscope
Properties of Light
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14. Properties of Light Reflection Transmission Absorption
Light strikes an object and bounces back
Transmission
Passage of light through an object
Must be one of these 2 for a microscope
Absorption
Taken up by that object and used as energy
Photosynthesis
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15. Properties of Light II Refraction
Bending of light as it passes through one medium to another of different density
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16. Properties of Light II Diffraction
Occurs when light rays are bent as they pass through a small opening, such as a hole, a slit, a space between two adjacent cellular structures, or a small, high powered, magnifying lens in a microscope.
The bent light rays distort the image obtained and limit the usefulness of the light microscope.
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17. Properties of Light Properties of Light Reflection
Strikes & bounces back.
Transmission
Passes through an object.
Absorption
Absorbed by object.
Refraction
Bends passing from medium to medium.
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18. Use of Immersion Oil With the Compound Microscope
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19. Immersion Oil Immersion Oil Same index of refraction as glass
Used to replace air to prevent refraction at a glass-air interface
Works as a “secondary lens”
Allows a clearer and larger image
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20. Review
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21. Review The Microscope Types of Microscopes Compound Electron
Properties of Light
Four Properties
Use of Oil Immersion
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