Microscope Notes

A lens bends light to make the image of an object appear smaller, larger, closer or farther away. Convex lenses concentrate light rays and are used as a magnifying lens. Concave lenses spread light rays.

A microscope uses light and lenses to produce an enlarged image of an object. Simple microscopes have only one lens. Compound microscopes have two or more lenses.

Parts of a Light Microscope

  1. Ocular - the magnifying lens closest to your eye.
  2. Body Tube - holds the lenses the proper distance apart.
  3. Revolving Nose Piece - holds the objective lens and allows objectives to be rotated for differing magnifications.
  4. Objectives are the lenses closest to the object (specimen).
  5. Scan objective is lowest power and shortest. Used to locate portion of specimen to observe.
  6. Low power objective - the middle length lens.
  7. High power objective - the longest length lens.
  8. Stage - supports the object (specimen).
  9. Stage Clips hold the object slides in place.
  10. Mirror - reflects light upwards through the slide.
  11. Substage Illuminator - shines light upwards through the slide.
  12. Base - supports the microscope.
  13. Diaphragm - controls the amount of light striking the slide.
  14. Arm - supports the body tube.
  15. Coarse adjustment knob - used to focus with scan objective.
  16. Fine adjustment knob - used to focus on low or high power objective.
  17. Inclination Joint - rotating joint so ocular can be positioned comfortably.

Procedure for using a Microscope

  1. Carry microscope with two hands, one on the arm the other on the base.
  2. With the arm towards you, place the microscope about 4" from the edge of desk/lab bench. Make sure power cords will not catch on the user or passersby.
  3. Verify the scan lens is in place and that the stage is a greatest distance from the scan lens.
  4. Look into ocular eyepiece; clean the lenses, mirrors or condenser if needed with lens paper.
  5. Place slide over hole in stage and secure with stage clips.
  6. Looking from the side, use the coarse adjust knob to bring the stage closest to the scan lens.
  7. Looking into the ocular, slowly increase the distance between the slide and the scan lens until the specimen is in focus.
  8. Locate area of specimen you wish to view.
  9. Slowly rotate nose piece until the low power lens clicks into place.
  10. On low and high power objectives, always use the fine adjustment knob, never use the coarse adjustment knob.
  11. Observe and sketch the specimen. To reduce eye strain, keep both eyes open.
  12. Never allow the objective lenses to contact a slide or specimen. If you must use the coarse adjust start again at step 6.
  13. When finished, rotate the scan objective into place.
  14. Use the coarse adjustment knob to drop the stage and remove the slide.
  15. Bring the body tube to an upright position and wrap the cord around the base.
  16. Return the microscope.