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

Parts of a Compound Light Microscope Image: Compound light microscope, Moisey Compound light microscope From the Virtual Microbiology Classroom on ScienceProfOnline.comVirtual Microbiology ClassroomScienceProfOnline.com Ocular Lens Objective Lens Arm Stage Coarse Focus Fine Focus Base Revolving Nosepiece Illuminator Condenser

Compound Light Microscope The “Compound” Part Simple microscopes have single magnifying lens (like a magnifying glass). Compound microscopes have two sets of lenses for magnification.Compound microscopes 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). The “Light” Part Bri ght-field light microscopes produce a dark image against brighter, backlit background. Provide a 2-D image. Commonly used to view stained cells. Image: Magnifying lamp use to look for part defects, US Navy; Compound light microscope, MoiseyMagnifying lamp Compound light microscope From the Virtual Microbiology Classroom on ScienceProfOnline.comVirtual Microbiology ClassroomScienceProfOnline.com

Human eye used to see these Light Microscope used to see these. Electron Microscope used to see these 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.

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

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 Microscopy: Electron Microscopes Images: Poliovirus, taken with TEM, PHIL #1875, Blood cells, taken with SEM, National Cancer Institute; Scanning electron microscope, Geological Survey of Israel laboratory.PHILBlood cells From the Virtual Microbiology Classroom on ScienceProfOnline.comVirtual Microbiology ClassroomScienceProfOnline.com