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MICROSCOPES

“illumination” Light (visible) Fluorescent U-V Electron. eyepieces Monocular Binocular. specimen background Bright field Dark field. MICROSCOPES. Resolving Power N.A. affects Wavelength affects. PARTS & TERMS. Lenses (ocular, objective) Total Magnification

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MICROSCOPES

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  1. “illumination” Light (visible) Fluorescent U-V Electron eyepieces Monocular Binocular specimen background • Bright field • Dark field MICROSCOPES Resolving Power • N.A. affects • Wavelength affects MICROSCOPES

  2. PARTS & TERMS • Lenses (ocular, objective) • Total Magnification • ocular mag. X objective mag. • Condenser • Diaphram MICROSCOPES

  3. PARTS & TERMS • Numerical Aperture (N.A.) optical characteristic of a lens N.A. = i sinq N.A. increases with magnification MICROSCOPES

  4. (l innm) R.P. = wavelength of illumination (2)N.A. PARTS & TERMS • Resolving Power (R.P.) • size of the smallest discernable detail • minimum distance between objects so that they are able to be distinguished as separate [ RP of human eye ~ 0.2mm = ______m ] MICROSCOPES

  5. l = 650nm, NA = 1.25 R.P. = l/2NA = _____nm = _____ m l = 450nm, NA = 1.25 R.P. = l/2NA = _____nm = _____ m Resolving Power (R.P.) l = 650nm, NA = 0.25 R.P. = l/2NA = _____nm = _____ m 1300 1.3 260 0.260 180 0.180 MICROSCOPES

  6. Resolving Power (R.P.) R.P. = l/2NA Larger or Smaller R.P. = BETTER ? • R.P. improves as N.A. increases or decreases? • R.P. improves as l increases or decreases? MICROSCOPES

  7. Types of Scopes MICROSCOPES

  8. Types of Scopes MICROSCOPES

  9. Types of Scopes Compound Light • Bright or Dark field • Use blue light or blue filter for shorter l • R.P. ~ 0.2m MICROSCOPES

  10. Types of Scopes Fluorescent • Dark field compound light microscope • Uses U-V for side illumination of specimen, fluorescent parts or dyes give off visible light that is viewed • R.P. ~ 0.2m MICROSCOPES

  11. Types of Scopes UltraViolet (U-V) • Uses U-V as illumination (shorter l) • Image recorded then viewed… still or video camera image(should NOT look directly at U-V!) • Special lens material (quartz),glass absorbs U-V • R.P. ~ 0.15m MICROSCOPES

  12. Types of Scopes Electron Microscopes • Use electron beam for illumination, magnets for “lenses”, video to view • Transmission Electron Microscope (TEM) • beam passes thru, view internal structure • Scanning Electron Microscope (SEM) • beam reflects, see external structure, texture MICROSCOPES

  13. Types of Scopes Transmission Electron Microscope (TEM) MICROSCOPES

  14. Types of Scopes Transmission Electron Microscope (TEM) • Special specimen preparation (vacuum) • Working magnification: whole bacteria….. 8,000x - 10,000x thin section, viruses…. 30,000x - 40,000x • Maximum magnification ~100,000x • R.P. ~0.001m = ______nm MICROSCOPES

  15. rickettsia herpes simplex

  16. Types of Scopes Scanning Electron Microscope (SEM) MICROSCOPES

  17. Types of Scopes Scanning Electron Microscope (SEM) • Special specimen preparation(vacuum & conductor) • Working magnification: 14,000x - 50,000x • Maximum magnification ~130,000x • R.P. ~0.01m = ______nm MICROSCOPES

  18. Q fever (rickettsia) Image enhancement

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