Bio.Lab-Ch.3 - Bio. Lab Chapter 3- Optical Microscopy 3.1...

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Bio. Lab Chapter 3- Optical Microscopy 1. 3.1 Structure and Function of the Light Microscope o Anything used to magnify an image is a microscope Light + lens= light microscope Must include 3 parts: Viewing medium Focusing apparatus Detection device For a long time, only a single piece of lens was used. It was called a biconvex lens . They are called simple microscopes When no actual image is projected, the image is called a virtual image . When an actual image is produced (like with an overhead) , then the image is called a real image . Modern microscopes are called compound microscopes . The basic features of the compound microscope are: Light travels from a light source through a collective of lenses called a condenser . The condenser serves to shape the direction of the light, control the intensity of the light, and the size of the beam that will hit the object. The light then travels through, reflects off of, and is absorbed by the object. When traveling from a higher refractive index to a lower refractive index, the rays will be bent to the opposite direction. When light rays pass from a lower refractive index to a higher refractive index, then they will be bent slightly perpendicular to the original path. After passing through the object, the light will either pass through air, lenses, or oil. They will travel in the direction dependent upon the medium through which they passed after traveling through the object. Then they will go through a magnifier called an objective .
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They will then pass through to another lens called the ocular (eyepiece). Then the individual will see a virtual image. Refer to Fig. 3-5 for labeled picture of microscope. Some microscopes may have a prism within the tube that will split the light into two separate ocular lenses. This is referred to as a binocular microscope. (some may even be triocular in which the third tube is used to photograph the image. Magnification of an individual lens is: Magnification of lens= length of image produced/length of actual image magnified This is referred to 43x or any other magnification on the objective. Magnification of the whole microscope is: Total magnification= magnification of the objective x magnification of the ocular Objects can be measured if the microscope is equipped with a measuring tool called a reticle . 2.
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This note was uploaded on 03/19/2008 for the course BIO 205L taught by Professor Hanson during the Fall '07 term at University of Texas.

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Bio.Lab-Ch.3 - Bio. Lab Chapter 3- Optical Microscopy 3.1...

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