The Microscope: Parts & Operational Use (Total Magnification & Safety\

During the historic period known as the Renaissance, after the "dark" Middle Ages, was the invention of the light microscope: an instrument that enables the human eye, with the help of a lens or combinations of lenses, to observe enlarged images of tiny objects. It is a fascinating way to look at certain things in such great detail. They have helped us out for many years with major discoveries in biology and medicine. Microscopes range from a simple magnifying glass to the expensive electron microscope. The compound light microscope is the most common microscope used in education today.


Parts of Microscope

Arm: support for the lenses and focusing gears
Body tube: the part through which light passes from one set of lenses to the next
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DNA using a microscope!

Objectives: parts that contain the lenses closest to the specimen. Examples: low, medium, high (the longer the lens, the higher the magnification)
Nosepiece: the rotating, circular part that supports two or three objectives with different magnifications.
Eyepiece: contains the magnifying lens, part nearest your eye when you are looking through the microscope.
Stage/stageclips: the stage is the flat platform on which you place the specimen
(usually on glass slide). The clips hold the slide in place.
Light source: light mounted below the stage (some microscopes may have mirrors), the light
source reflects light through the opening in the stage, and through the sample.
Diaphragm: device that regulates the amount of light passing up towards the eyepiece.
Coarse adjustment: moves body tube to focus image. Should only be used when a specimen is under
LOW power, otherwise slide may break.
Fine adjustment: moves body tube slightly to adjust the image. Can be used under any power.

Formula for Total Magnification:

magnifying power of eyepiece (what the DNA is looking into) x magnifying power of objective (either low, medium or high, under where hands are) →
ex: 10 x 40= 400x

Safety of Microscope:

  • When carrying microscope place one hand beneath the base and grasp the arm of the microscope with the other hand
  • A click indicates that the lens is in line with the opening of the stage
  • Clean the lens with the lens paper provided
  • After every use, it is important to remove the slide and return the low-power objective into place in line with the body tube
  • Use a papertowel/lens paper at the edge of the coverslip opposite to where a drop of stain was placed so if the specimen begins to dry out, add a drop of water at the edge of the coverslip


Slide and Coverslip
Slide and Coverslip





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