Microscopes Winter 2009 post

Microscopes Winter 2009 post - x Beam of electrons for...

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Microscopes !! x Magnification : Ratio of the size of the image to the size of the object. x Resolving power : Ability of an optical system to distinguish between two objects that are very close together. x Rule : Objects closer than ½ of the light source wavelength can not be resolved. x Light microscopes (400-700 nm) x Wavelength : the distance between 2 corresponding points on 2 adjacent waves (measured in nanometers). x Nanometer (nm) : one billionth of a meter. 1. Stereo Microscope x Stereo Microscope : x Maximum magnification about 250 X x White Light as a Radiation Source. Working Distance ! 2. Compound Microscope x Compound Microscope : x Maximum magnification about 1,500 X x White Light as a Radiation Source. Working Distance !! A Little History x Early 1900's, look for improvement.
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Unformatted text preview: x Beam of electrons for radiation source. x Electrons travel in waves - wavelength = 0.05 nm. x Maximum magnification 500,000 X. x Images are sharper, very detailed & able to see cell's organelles . x Knowledge greatly enhanced of specific cellular, bacterial, viral and other "minute" functions ! x Live specimen viewing not possible 3. Electron Microscope x Scanning Electron Microscope (SEM) x Transmission Electron Microscope (TEM) Electron Microscopes continued x Transmission Electron Microscope (TEM) x Samples must be cut very, very thin**. x Can see internal details. x Scanning Electron Microscope (SEM) x Whole samples can be used **. x Ability to see external features of sample....
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