Using a light microscope

• Function of a stage micrometer

  • calibrate an eyepiece graticule so that it can be used to make measurements
• How to calibrate an eyepiece graticule

  • select desired magnification and objective, place micrometer on the stage
  • line up the scales of the micrometer and the eyepiece graticule
  • count the number of divisions on the eyepiece graticule equivalent to 1 division on the stage micrometer
  • calculate the length of one division of the eyepiece graticule
• Preparing a slide

  • stain sample
  • mount sample on the slide
  • place cover slip carefully on the slide, avoiding air bubbles
• Magnification formula

  Magnification = size of image / actual size of object
• procedure of focusing with a light microscope

  • rotate the revolving nosepiece to line up the lowest power objective lens
  • look through the eyepiece and use the coarse adjustment knob to lower the stage to focus the image
  • use the fine adjustment knob to focus the image further
• Light microscope types

  A) coarse adjustment knob

  B) eye piece

  C) revolving nose piece

  D) objective lens

  E) stage

  F) box

  G) fine adjustment knob