While working as an instructor at the McCrone Research Institute (McRI), the presenter discovered a small wooden box labeled (in Walter McCrone’s handwriting) “Abbe Diffraction Test Kit.” Curiosity led him to open it, and what he found helped to deepen his understanding of what he had learned as a student in McRI courses about Abbe’s theory of resolution. Ernst Abbe (1840-1905) theorized that in order to resolve the detail in a specimen with fine spacing, consecutive orders of the diffraction pattern produced by the specimen must be collected by the objective lens. He created a small kit containing a number of specimens and apertures that can be used to demonstrate his theory. This presentation will discuss how the kit can be used to illustrate these principles. A variety of experiments will be performed using the diffraction test kit, and the results of the experiments will be related directly to Abbe’s theory of resolution by using the light microscope.

Bio Sketch
Andrew Bowen earned a B.S. in Chemistry from the University of Virginia and an M.S. in Forensic Science from the University of Illinois at Chicago. He worked full time as Research Microscopist and Instructor at the McCrone Research Institute in Chicago from 2001 until 2004 and is currently Forensic Microscopist with Stoney Forensic, Inc. He continues to teach at the McCrone Research Institute as an adjunct instructor.