Anna Mae Preston, age 13, of Dayton, Ohio, for her question:
WHO MADE THE FIRST MICROSCOPE?
A microscope is an instrument that magnifies tiny objects so they can be seen easily. Glass globes filled with water were used by early day engravers as magnifying glasses. Microscopes of this type were probably used for the first time more than 3,000 years ago.
A magnifying glass is actually the simplest optical microscope. The best one, however, can only magnify an object by 10 to 20 times. It cannot be used to magnify an object any further because the image becomes fuzzy.
Historians tell us that the Romans may have made magnifying glasses from rock crystals, but glass lenses of the type now used weren't introduced until the late 1200s.
A Dutch spectacle maker, Zacharias Janssen, is credited for having discovered the principle of the compound microscope about 1590. Then, in the mid 1600s, a Dutch amateur scientist named Anton van Leeuwenhoek made a microscope lens that could magnify up to 270 times. He built simple microscopes more powerful than the compound devices of his day and is said to have been the first person to observe microscopic life and record his observations.
Until the early 1800s, few improvements were made in the microscope. Then glass making methods improved and lenses were made that provided undistorted images.
An optical instrument manufacturer from Canastota, N.Y., named C.A. Spencer, was the first American to manufacture a microscope when he came up with the design in 1838.
The first electron microscope in the world was demonstrated by German scientists in 1931.
Today's optical microscope has one or more lenses that bend the light rays shining through a specimen of whatever is being examined. The bent light rays join and form an enlarged image of the specimen.
Today the microscope definitely ranks high on the list of science's the most important tools.
With microscopes, doctors and other scientists are able to examine tiny objects such as blood cells and bacteria. The entire world of organisms too small to be seen by the unaided eye is revealed to the person with a microscope.
There are three basic kinds of microscopes: optical or light, electron microscopes and ion microscopes.
Scientists use a number and the abbreviation "X" to indicate the image of an object magnified a certain number of times or a lens that magnifies by that number of times. A 10X lens, for example, magnifies an object by 10 times.
The magnification of a microscope may also be expressed in units called diameters. A 10X magnification enlarges the image by 10 times the diameter of the object.