1. Basic Microscopy SC.912.L Compare and contrast structure and function of various types of microscopes.
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Image: The Far Side by Gary Larson

2. Compound Light Microscope
Compound microscopes have two sets of lenses for magnification.
ocular lens = Lens closer to the eye (magnifying power of 10x).
objective lens - Lenses closer to the object being viewed (Most light microscopes used in biology have three or four objective lenses).
Produce a dark image against brighter, backlit background.
Provide a 2-D image of thinly sliced specimens on a slide.
Commonly used to view stained cells.
Image: Magnifying lamp use to look for part defects, US Navy; Compound light microscope, Moisey
From the Virtual Microbiology Classroom on ScienceProfOnline.com

3. Stereoscopic (Dissecting) Microscope
Used for viewing live specimens or three-dimensional objects too large or thick to be accommodated by compound microscopes.
Not as powerful as compound microscopes

4. Electron Microscopes
Used to observe VERY small objects: viruses, DNA, parts of cells
Uses beams of electrons rather than light
Electron beam wavelengths are shorter than light wavelengths, so better resolving power.
Transmission Electron Microscope (TEM): 2-D image, see through the specimen
Scanning Electron Microscope (SEM): 3-D image, see surface of the specimen
Images: Poliovirus, taken with TEM, PHIL #1875, Blood cells, taken with SEM, National Cancer Institute; Scanning electron microscope, Geological Survey of Israel laboratory.
From the Virtual Microbiology Classroom on ScienceProfOnline.com

5. What is the difference between electron microscope and light (optical) microscope?
• Electron microscope uses an electron beam, while an optical microscope uses a light beam.
• The maximum magnification of the optical microscope is about 2000x, where the maximum magnification of the electron microscope is about 10,000,000x.
Human eye used to see these
Light Microscope used to see these.
Electron Microscope used to see these