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Microscopes

Microscopes. How can we observe cells?. What technology allows biologists to study microscopic life?. A. Compound Light Microscope Has two lenses – ocular (eyepiece) and objective

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Microscopes

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  1. Microscopes • How can we observe cells?

  2. What technology allows biologists to study microscopic life? • A. Compound Light Microscope • Has two lenses – ocular (eyepiece) and objective • In order to be viewed, specimen must be thin (so the light may shine through the specimen) and placed on a slide. • Specimen may be stained to better see structures

  3. Fill It In … Label the ocular lens and the objective lens:

  4. Diaphragm Base Always carry a microscope with one hand holding the arm and one hand under the base. Ocular lens(Eyepiece) Body Tube Nosepiece Arm Objectives Stage Stage Clips Coarse Adjustment Fine Adjustment Light

  5. What technology allows biologists to study microscopic life? • B. Electron Microscope • Uses electrons to produce an image • Types: • Scanning Electron Microscope (SEM) • Electrons scan the surface of a specimen • Produces a 3-D image

  6. What technology allows biologists to study microscopic life? • B. Electron Microscope • Transmission Electron Microscope (TEM) • Designed to look at structures inside a cell • Capable of greatest magnification

  7. What technology allows biologists to study microscopic life? C. Limitations of microscopes Magnification is limited by the strength of the lens. Calculating magnification: Ocular lens x objective lens = total magnification Example: Ocular (10x) x objective (40x) = 400x As magnification increases resolution/(sharpness) decreases.

  8. What’s my power? To calculate the power of magnification, multiply the power of the ocular lens by the power of the objective. What are the powers of magnification for each of the objectives we have on our microscopes?

  9. We can see better details with higher the powers of magnification, but we cannot see as much of the image. Which of these images would be viewed at a higher power of magnification? Comparing Powers of Magnification

  10. Check Yourself! • Why must specimens be thin for a compound light microscope? • Which microscope provides the highest possible magnification? • If the ocular lens is 10x and the objective lens is 10x then the total magnification is? • As magnification increases, resolution _______________

  11. Check Yourself! • Why must specimens be thin for a compound light microscope? TO ALLOW LIGHT TO PASS THROUGH THE SPECIMEN • Which microscope provides the highest possible magnification? • If the ocular lens is 10x and the objective lens is 10x then the total magnification is? • As magnification increases, resolution _______________

  12. Check Yourself! • Why must specimens be thin for a compound light microscope? TO ALLOW LIGHT TO PASS THROUGH THE SPECIMEN • Which microscope provides the highest possible magnification? TEM (TRANSMISSION ELECTRON) • If the ocular lens is 10x and the objective lens is 10x then the total magnification is? • As magnification increases, resolution _______________

  13. Check Yourself! • Why must specimens be thin for a compound light microscope? TO ALLOW LIGHT TO PASS THROUGH THE SPECIMEN • Which microscope provides the highest possible magnification? TEM (TRANSMISSION ELECTRON) • If the ocular lens is 10x and the objective lens is 10x then the total magnification is? 10 X 10 = 100X • As magnification increases, resolution _______________

  14. Check Yourself! • Why must specimens be thin for a compound light microscope? TO ALLOW LIGHT TO PASS THROUGH THE SPECIMEN • Which microscope provides the highest possible magnification? TEM (TRANSMISSION ELECTRON) • If the ocular lens is 10x and the objective lens is 10x then the total magnification is? 10 X 10 = 100X • As magnification increases, resolution _DECREASES_

  15. Cheek Cells!

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