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How Microscopes Work



How Microscopes Work
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     edHelper's suggested reading level:   grades 6 to 8
     Flesch-Kincaid grade level:   8.36

Vocabulary
     challenging words:    convex, determined, eyepiece, magnification, multiplying, inward, microscope, electron, optical, objective, lead, wavelength, original, power, outward, often


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How Microscopes Work
By Cindy Grigg
  

1     Inventions often lead scientists to make new discoveries. One of the most important discoveries in life science was the microscope. A microscope is used for looking at things too small to be seen with just our eyes. A light (also called an optical) microscope uses a convex lens to bend light rays. A convex lens is a lens that bends outward. It is thicker in the middle than at the edges. This shape causes light rays to bend inward and meet at a point. When you look at an object through a convex lens, the object looks larger. A light microscope might have a single lens or more than one lens. If it has more than one lens, it is called a compound microscope.
 
2     The eyepiece is the part of the microscope you look through. There is a lens in the eyepiece which usually has a magnifying power of 10X. The other lens is located in a part called the objective. Usually there are two objectives. One is high power and the other is low power. The magnifying power of the objectives can be found by looking on the side of each objective.
 
3     A compound microscope has two or more lenses. The magnification power of a compound microscope is determined by multiplying the powers of the lenses. For example, if one lens has a magnification power of 10X and another lens has a magnification power of 40X, the microscope's magnification power is 400X. An optical microscope usually has at least three different objective lenses so that different magnifying powers can be chosen.

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