Light Microscopes

The Light Microscrope, also called the Optical Mircroscope, is the the most readily used and well known research tool of Biology. One unique feature the Light Microscope has is that the user can see the objects in color, where as, the Electron Microscope cannot. There are two types of Light Microscopes, the simple, a microscope with one lens, and the compound, a microscope with multiple lens. However, each does the following (Watson):

·         Uses visible light to illuminate the object

·         Relatively inexpensive

·         Can examine live or dead objects

·         Magnification: increase in diameter or size; ocular lens ( 10X )

·         As magnification increases, resolution decreases

·         Miss many cell structures

o   Lysosomes, centrioles

·         Fluorescence, phase-contrast, confocal

Electron Microscopes

The Electron Microscope uses electrons to enable the user to see enlarged images of the object. This specific type of microscope can magnify up to two million times larger than the original size, where as, the most sophisticated Light Microscope can only enlarge up to two thousand times. The Electron Microscope (Watson):

·         Beams of electrons instead of light

·         1939, used more after WW2

·         Higher magnifications

·         Can get down to atomic level in some cases

·         Needs a vacuum

·         Specimen must stop the electrons

·         Expensive equipment

·         Specimen preparation

Transmission electron microscope

·         Sends electrons through thinly sliced and stained specimens

·         Higher magnification of INTERIOR views

·         Specimen is dead; prep is difficult

Scanning electron Microscope

·         Excellent view of SURFACES

·         3-D

·         Live specimens possible

·         Lover magnifications

·         Only see surface of specimen
 

(Friedman)

Works Cited

http://images.google.com/imgres?imgurl=http://techluver.com/wp-content/uploads/2007/12/carl_zeiss_100kv_transmission_electron_microscope.jpg

http://www.dsbn.edu.on.ca/schools/Westlane/Science/simon/SBI3C1/micro.gif

"Keller, Amy. "Chapter 6: A tour of the Cell." 21 Sept 2008.

"Optical Microscope." Wikipedia. 2008. 21 Sep 2008 <http://en.wikipedia.org/wiki/Optical_microscope>. 

"Electron Microscope." Wikipedia. 2008. 21 Sep 2008 <http://en.wikipedia.org/wiki/Electron_microscope>.