EN212-01191
GHW2: Mechanism Description (draft)
August 15, 2012
COMPOUND MICROSCOPE
A compound microscope is an optical instrument used to see objects that are too small for the naked eye.
A compound microscope is a microscope fitted with two or more convex lenses. The high magnification produced by these lenses together enables a detailed study of micro-organisms, cells and tissues. These types of microscopes are therefore widely used in scientific and medical research.
The basic design of a compound light microscope consists of convex lenses fitted at either end of a hollow tube. This tube is fitted on an adjustable, rotary nosepiece. There is an adjustable stage under the nosepiece; specimen slides are placed or fitted on this stage for observation through the lenses. The stage has a window or hole in it through which a light source can illuminate the specimen under observation (see Figure 1).
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The light from the light source passes through the specimen, resulting in an image that your naked eye would ordinarily see if looking at the slide. The image is then magnified by the lower (objective) lens. The objective lens flips the image and magnifies it by bending the light. The light is bent as it passes through the convex surface on either side of the lens material. The eyepiece acts as a weaker version of the objective lens by flipping the image again and magnifying it further.
Compound microscopes are used most commonly to magnify thin sections of specimens placed on slides. The 400x compound microscope is used by almost every college level biology student.
Almost every scientific field has found use, at some point, for magnifying small objects. Microscopes are probably used most often in biological and chemistry related fields. They are routinely used in hospitals for diagnosis and research, and are common