Biology #2

• Microscope - Is a tool too see organisms or objects that are too small to be seen by the naked eye
• Magnification - it describes how much larger an object appears when viewed
• Resolution - is the ability to distinguish between two closely spaced points on an image
• Compound Microscope - is an optical microscope that uses visible light to form an image
• Three Major Parts

  1. Magnifying
  2. Illuminating
  3. Mechanical
• Magnifying Parts - The parts that make the specimen look bigger
• Eyepiece/Ocular - where the viewer looks and see the magnified image of the specimen
• Objective lenses - the major lenses used for specimen visualization/ magnification
• Low power objective - it has magnification power of 10x. it is used to see the general outline of the specimen
• High power objective - it has a magnification power of 40x, it is used to view structures from a larger perspective
• Oil Immersion Objective - it has a magnification power of 100x. it requires the special use of oil
• The three types of Objective Lenses

  1. Low Power objective
  2. High power objective
  3. Oil Immersion objective
• Illuminating parts - the parts of the microscope that supply and regulate light towards the specimen
• MIrror - it reflects light from an external light source
• Iris Diaphragm - it controls the amount of light that reaches the specimen
• Stage condenser - it collects and focuses the light
• Mechanical Parts - these parts are used for support and in adjusting the different parts of the microscope
• body tube - holds the eyepiece lens and connects them to the objective lenses
• revolving nosepiece - it holds the different objective lens and facilitates the changing of objectives
• Adjusting Knob - they are used to focus the microscope
• Coarse Adjustment knob - it moves the body tube and low power lenses closer or farther away from the stage
• Fine adjustment - it is used to bring the specimen into shart focus to show clearly the detailed parts of the specimen
• 2 types of adjustment knobs

  1. Coarse Adjustment Knobe
  2. Fine adjustment knob
• Stage - a flat surface where the mounted slides is places
• stage clips - holds the slides in place
• arm and base - used for support in carrying the microscope
• inclination joint - allows user to tilt the microscope
• 1. Eyepiece
  2. Body tube
  3. Revolving nosepiece
  4. objective lenses
  5. Stage
  6. Diaphragm
  7. Mirror
  8. Coarse ADjustment knob
  9. Fine adjustment knob
  10. arm
  11. Stage clips
  12. Inclination joint
  13. base

  A) Body tube

  
• Types of microscope

  • Dissecting Microscope
  • Compound Microscope
  • Scanning Electron Microscope (SEM)
  • Transmission Electron Microscope (TEM)
• Circa 100AD - the first vision aid was invented called a reading stone
• Circa 1284 - Italian Salvino D' armate is credited with inventing the first wearable eye glasses
• 1590 - two dutch eye glass maker Zacharias Janssen and Hans Janssen experimented with multiple lenses placed in a tube. Creating the compound and the telescope
• 1665 - english physicist Robert hooke looked at a silver of a cork through a microscope lens and noticed ''pores'' ''cells''
• 1674 - Anton van leeuwenhoek built a somple microscope with only one lens to examine blood, yeast, incest, and more. He was the first to describe bacteria
• 1830 - Joseph Jackson lister reduces spherical abberation of the ''chromatic effect''
• 1872 - Ernst Abbe then research director of the Zeiss Optical works wrote a mathematical formula called ''Abbe Sine Condition'' his formula provided calculations that allowed for the maximum resolution
• 1903 - Richard Zsigmondy developed the ultramicroscope that could study objects below the wavelength of light
• 1932 - Frits Zernike invented the phase contrast microscope
• 1931 - Ernst Ruska co-invented the electron microscope
• 1981 - Gerd Binnig and Heinrich Rohrer invented the scanning tunneling microscope that gives three-dimensional images of objects down to the atomic level