Microscope Parts: From the Base Up
Before working with a microscope it is good to have a thorough understanding of all the parts of a microscope and their functions. We will begin at the base and work our way up:
- The base stabilizes the apparatus. When a microscope is being carried, one hand should be under the base and one gripping the arm.
- The light to illuminate the specimen comes from the light source. In many microscopes, this is a small bulb, but the ultimate light source may be from a lamp or even a candle - redirected by a mounted mirror. The microscope in our illustration gives the viewer a choice of either a mirror or a bulb.
- The stage is a kind of plate upon which a slide with a specimen can be mounted. Most microscopes will have two clips to hold the slide in place. There will be a hole in the middle of the stage to allow light from the source to strike the specimen.
- An arm connects the base with the upper apparatus of the microscope. It keeps the base separate from the viewing portion of the microscope, allowing it to be adjusted, even as the stage remains stable.
- There are usually three or four objective lenses attached to the revolving nosepiece. This combination allows the magnification level to be changed, by a simple process of turning the nosepiece which changes lenses. The objective lenses will vary in magnification level from possibly 4 times to 100 times. (The image will later be magnified again by the ocular lens in the eyepiece.)
- The tube connected with the arm adjusts up and down using the focus. This moves the lenses closer to or farther from the specimen. On some microscopes there is both a coarse and a fine adjustment.
- The eyepiece contains the ocular lens, which gives the image an additional magnification, usually ten times. It is through this lens that the viewer sees the image of the specimen.