Changes

==Optical compound microscopes==

==Optical compound microscopes==

Optical compound microscopes are broadly similar to telescopes in containing two widely separated lenses or systems of lenses: an ''ocular'' or ''eyepiece'' that you look into, and an ''objective'' which is close to the object that is being observed.

Optical compound microscopes are somewhat similar to telescopes in that their basic design is a tube, with holding a lens or a system of lenses at each end of the tube. A microscope consists of an ''ocular'' or ''eyepiece'' that you look into, and an ''objective'' which is close to the object that is being observed.  

Such microscopes can magnify from about 10 to 1000 times.  

Such microscopes can magnify from about 10 to 1000 times.  

The higher powers, however, require special techniques; the object to be observed must be prepared as a flat, thin section, usually stained with special chemicals to make transparent structures visible, cemented under a cover-glass, and used with a special oil-immersion objective, with a drop of oil between the objective and the cover slip. Microscopes in children's science kits may claim high magnifications, but anything over about 50X is "empty magnification" and of no use.

The higher powers, however, require special techniques; the object to be observed must be prepared as a flat, thin section, usually stained with special chemicals to make transparent structures visible, cemented under a cover-glass, and used with a special oil-immersion objective, with a drop of oil between the objective and the cover slip. Microscopes in children's science kits may claim high magnifications, but anything over about 50X is "empty magnification" and of no use.