Microscope - by Jacob Eapen

Microscope

Magnification lenses have been known about since ancient times. The modern microscope which used a compound lens system were developed between 1590 and 1610. The first microscope is credited to the father and son, Hans and Zacharias Jannsen, in 1600. In 1611 Johannes Kepler invented a microscope using a convex lens in the eyepiece. The microscope slowly developed over the years when in about 1900 the microscope became what it is today.

An optical microscope has one or more lenses that bend light rays shining through the specimen. The simplest optical microscope is a magnifying glass. You can get more magnification if the microscope has two lenses, an objective lens and ocular lens, or eyepiece. The objective lens magnifies the specimen, while the ocular lens magnifies the image that the objective lens created into an even bigger lens. How clear a microscope can produce an image is called resolving power. Optical microscopes can only produce images larger than a light wave length, thus not able to produce images of atoms and molecules.

Electron microscopes are able to magnify much more than optical microscopes. It is a tool used much by researchers to research biology, medicine, and metallurgy. These microscopes can magnify more than optical microscopes because it has a larger resolving power due to the fact that the electrons in its beam has shorter wave lengths than a light beam. The two types of electron microscopes are transmission electron microscopes and scanning electron microscope. Transmission electron microscopes can magnify from 50 to 1,000,000 times, and scanning electron microscope can magnify 5 to 500,000 times. Optical microscopes can only magnify up to 1,500 times.

Photographic microscopes are used to examine objects or organisms more closely by taking a photograph. If a photo of microorganisms are being taken they must be killed with formalin, or else they will blur the photograph.

A microtome is an instrument used to cut very thin slices of plant and animal tissues. Microtomes are needed to cut so thin so that light can pass through it hence microscopes are able to produce images of them.

A magnification calculation is how much a microscope magnifies. An example of this is that say the objective lens magnifies 20 times and the ocular lens magnifies 15 times. To find out how much the microscope magnifies you need to multiply20(15)=300. 300 is how much the microscope magnifies.