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Microscopy

Microscopy. What is a microscope?. A scientific tool that helps scientists see things that cannot normally be seen with the “naked” eye. History. Hans and Zacharias Janssens-1590s, Dutch Eyeglass Makers, Inventors Early microscope was composed of a tube with lenses at both ends

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Microscopy

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  1. Microscopy

  2. What is a microscope? • A scientific tool that helps scientists see things that cannot normally be seen with the “naked” eye.

  3. History • Hans and Zacharias Janssens-1590s, Dutch Eyeglass Makers, Inventors • Early microscope was composed of a tube with lenses at both ends • Magnification ranged from 3X to 9X

  4. History • Robert Hooke- 1635-1703, English Chemist, Mathematician, Physicist, and Inventor • Improved the compound light microscope and observed cork (bark of an oak tree) and coined the term cells. They resembled cells, which are rooms in monasteries.

  5. History • Anton van Leeuwenhoek- 1632-1723, Wine Assayer, Surveyor, Cloth Merchant, Minor Public Official, and Inventor • Made the best one-lens microscope of his time. • He observed bacteria from teeth scrapings and protozoa from pond water. He called them “weebeasties” and “animalcules.”

  6. Compound Light Microscope Anatomy • Microscope • Resources available from sciencespot.net • Diagram of Light Microscope • Microscope Quiz • Microscope Crossword Puzzle

  7. Proper Microscope Care and Technique • How do you carry a microscope? • Always begin focusing on which objective? • Only use the fine adjustment knob for which objective? • How do you properly store a microscope?

  8. Using a Microscope in Lab • Always make sure the stage is all the way up when focusing and slowly bring the stage down. • When on low power, use the course adjustment knob (the big knob) • When on high power, use the fine adjustment knob (the little knob) • NEVER use the course adjustment knob on high power!!! Why? STOP

  9. Other Notes… • Center the object in the field of view NO! YES!

  10. Other Notes… • Microscopes are parfocal- you can focus on scanning objective and switch to low-power and high-power objectives with minor adjustments in focusing • At higher magnification, less light appears to pass through a specimen • Wet mounts are temporary

  11. Other Notes… • Modern light microscopes are limited to 2000X due to lens optics • Or higher powers of magnification, different types of microscopes are needed- they DO NOT USE LIGHT

  12. Effect of Changing Objectives from Scanning to Low to High Power

  13. Types of Microscopes Follow the following link: http://www.cas.muohio.edu/mbi-ws/microscopes/types.html

  14. Stereoscope/Dissecting Microscope • Used in dissections • Images are NOT inverted

  15. Scanning Electron MicroscopeSEM • Sweeps a beam of electrons over the surface of a specimen • Approx. 60,000X magnification (max.) • Example

  16. Transmission Electron Microscope (TEM) • Aims a beam of electrons through a specimen • Magnifies +100,000X

  17. Scanning Tunneling Microscope/Probe (STM) • Electrons flow from the tip of the probe and the surface of the specimen • Magnifies up to 100 million times (100,000,000X) • Can see the surface of atoms!

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