Light+Microscopes

=Introduction to light microscopes= toc =What is a light microscope?= A light microscope is a scientific tool used to observe small objects using visible light and lenses. The lightmicroscope is the most recognized microscope in the scientific community. Light microscopes can be used to view living or dead samples from 10x to maximum 1000x. A light microscope is composed of an objective lens, an ocular lens, a stage, a light source, a condenser, a tube, an arm to support the tube, and a focusing system. Two metal clips usually hold down the specimen that is being viewed. The light bulb is beneath the stage so that the light shines up through the specimen. The tube focuses down on the specimen and stage so that the ocular lens or eyepiece is at the end of the tube and the objective lens is at the end closer to the specimen.

A telescope must gather large amounts of light from a dim, distant object; therefore, it needs a large objective lens to gather as much light as possible and bring it to a bright focus. Because the objective lens is large, it brings the image of the object to a focus at some distance away, which is why telescopes are much longer than microscopes. The eyepiece of the telescope then magnifies that image as it brings it to your eye.

=What is a compound light microscope?= A compound microscope is a microscope which uses multiple lenses to collect light from the sample and then a separate set of lenses to focus the light into the eye. Compound microscopes are heavier, larger and more expensive than simple microscopes due to the increased number of lenses used in construction. The main advantages of multiple lenses are improved numerical openings reduced chromatic oddness and exchangeable objective lenses to adjust the magnification. A compound microscope also makes more advanced lighting setups, such as phase contrast

=What is a magnifying glass?= A magnifying lens is a lens or many lenses used to magnify or enlarge an object. Magnifying glasses allow people to magnify a variety of objects (e.g. books, newspapers, fine print, and jewellery). The magnifying glass was invented in 1250 by Roger Bacon. Today, over 750 years later magnifying glasses are more popular than ever, assisting people with hobbies and crafts and also helping people with low vision to see better. =What is the difference between a compound light microscope and a magnifying glass?= (1) Magnifying Glass is usually a single lens - a compound light microscope would have multiple lenses working (at least 2 in tandem).

(2) A magnifying glass you move it to get clarity (single magnification), a compoung microscope has focussing features and multiple magnification.

(3) Obviously a compound light microscope would be more expensive than the magnifying glass.

(4) Magifying glass usually rely on external light source, an advanced compound microscope comes with its own light source  =Definitions= =Sources= .@http://www.wisegeek.com/what-is-a-light-microscope.htm
 * Term || Definition ||
 * Compound light microscope || A microscope which uses multiple lenses to collect light from the sample and then a separate set of lenses to focus the light into the eye. ||
 * magnifying glass || A lens used to enlarge an object. ||
 * light microscope || A scientific tool used to observe small objects using visible light and lenses. ||

.@http://simple.wikipedia.org/wiki/Light_microscope

. @http://www.wisegeek.com/what-is-a-compound-microscope.htm

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