Anyone who has taken high school biology has encountered a dissecting microscope; it was usually accompanied by a frog. The trauma involved in having to chloroform destroy a frog in the name of education may, however, have rendered you oblivious to the workings of the dissecting microscope, so here is a refresher course on how it was constructed and how it worked.
Construction Of A Dissecting Microscope
The dissecting microscope, like all microscopes, has a tube with a lens at its upper opening, through which you look to view the specimen lying beneath the tube's lower end. The upper end of the tube will also have some form of nose piece to help your head remain steady while you do your viewing.
The lower end of the dissecting microscope contains the second lens, known as the “objective“ lens. The type of objective lens being used will depend on how fine a focus you need to examine your specimen. Your dissecting microscope will have two more light-condensing lenses in its condenser; these lenses are responsible for the microscope's magnification capacity.
The dissecting microscope's condenser is centered above the middle of the microscope's stage, on which the slide bearing the specimen ifs placed for examination. The best dissecting microscopes have adjustable stages which can be manipulated without the microscope's user having to remove his or her eyes from the eyepiece.
The dissecting microscope's stage is positioned above its diaphragm, the function of which is to control the amount of light being transmitted through the slide and specimen. The light itself is also below the dissecting microscope's stage, and is either a halogen or fluorescent bulb. It is the manipulation of the light's reflection on the specimen that causes the dissecting microscope to magnify what the user sees.
Caring For A Dissecting Microscope
Dissecting microscopes, like all others, require special care; their lenses should be kept dust and smudge free with dry, soft cloths and they should be stored, when not in use, in dust covers. They should also be stored away from dampness.
Those handling a dissecting microscope should always carry it in both hands. That is the best way to avoid either dropping it or bumping it against other objects; either of which will ruin the alignment of the lenses. The dissecting microscope is most secure when its user holds the microscope arm in one hand and supports its base in the other.
