CHE 113 Lecture 4: Chapter 4 lecture microscopy
10 Feb 2017
School
Department
Course
Professor
Document Summary
Chapter 4: dutch spectacle-makers (1590), janssens, discovered that nearby objects appeared greatly enlarged with lenses, galileo (late 1600s), based on the janssens experiments, worked out a much better instrument with a focusing device. Compound light microscope: most common microscope; two sets of lenses: ocular and objective, total magnification: multiply magnification of the objective lens with the ocular lens. Ocular is 10x and objective is 100x: optical system comprised of condenser, objective lens, eyepiece lens and illuminator, the compound light microscope uses visible light, virtual image is any specimen viewed through a lens. Important tool for firearms examiner: two compound microscopes combined into one unit, when viewer looks through eyepiece, a field divided into two equal parts is observed. Phase-contrast microscope: splits a beam of light into two types, direct and refracted and brings them together to form an image of the specimen, enhances contrast, allows detailed observation of living organisms, especially internal structures.
