FORS-2106EL Study Guide - Quiz Guide: Digital Evidence, Zacharias Janssen, Antonie Van Leeuwenhoek
27 Jun 2018
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FORS-2106 - Lab 1 Quiz Review
-Another common practice in all forensic labs is that known material never gets
examined on the same workbench, or sometimes even in the same room, as
unknown material. Obviously this is to avoid any potential for cross-contamination
-A very simple optical (or light) microscope is a magnifying lens or hand loupe,
composed of one convex lens. The most common device of this type still in use by
forensic scientists today is the fingerprint magnifier. These are high quality lenses,
designed to produce as little distortion as possible, mounted on a small stand, for
comparison of known to unknown prints
-Ocular Magnification x Objective Magnification = Total Magnification
-depth of focus’ is the thickness of an object that is in focus at any given point
Definitions:
-Antonie Van Leeuwenhoek: Dutch tradesman and scientist, the first person to
observe and describe single celled organisms, which he originally referred to as
animalcules (which we now refer to as microorganisms). He was also the first to
record and observe muscle fibres, bacteria, spermatozoa and blood flow in capillaries
(small blood vessels).
-Hans Jansen: Dutch spectacle-maker, believed to be the first creator of a compound
microscope with his sun Zacharias Jansen
-Working distance: defined as the distance from the front lens element of the
objective to the closest surface of the coverslip when the specimen is in sharp focus
-Numerical aperture: a measure of its ability to gather light and resolve fine specimen
detail at a fixed object distance
-Focal depth: the max distance that you can place the lens from the object while
keeping it in focus
-Resolving power: defined as the ability of a microscope or telescope to distinguish
two close together images as being separate
-Field number: 10x refers to the magnification of the eyepiece. Total magnification of
the microscope is a combination of the eyepiece and the objective lens being used.
20 - This is the field number, in this case the eyepiece has a field number of 20mm
-Diptera: True flies are insects of the order Diptera, Insects of this order use only a
single pair of wings to fly
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Document Summary
Another common practice in all forensic labs is that known material never gets examined on the same workbench, or sometimes even in the same room, as unknown material. Obviously this is to avoid any potential for cross-contamination. A very simple optical (or light) microscope is a magnifying lens or hand loupe, composed of one convex lens. The most common device of this type still in use by forensic scientists today is the ngerprint magni er. These are high quality lenses, designed to produce as little distortion as possible, mounted on a small stand, for comparison of known to unknown prints. Ocular magni cation x objective magni cation = total magni cation. Depth of focus" is the thickness of an object that is in focus at any given point. Antonie van leeuwenhoek: dutch tradesman and scientist, the rst person to observe and describe single celled organisms, which he originally referred to as animalcules (which we now refer to as microorganisms).
