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The programme examines the usefulness of the model building approach for obtaining information about objects from their diffraction patterns. Similarity between diffraction of light and x-rays is d...emonstrated.
Metadata describing this Open University video programme
Module code and title: ST291, Images and information
Item code: ST291; 06
First transmission date: 12-05-1977
Published: 1977
Rights Statement:
Restrictions on use:
Duration: 00:24:23
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Producer: Ted Smith
Contributors: Stuart Freake; Charles Taylor
Publisher: BBC Open University
Keyword(s): Asbestos fibres; Atomic level; Diffractometer; Hexa-methyl benzene; Optical diffraction analogue; X-ray diffraction patterns
Footage description: Shots of optical diffraction patterns of blue asbestos fibres in and outside a magnetic field. Stuart Freaks introduces the programmme. Prof. Charles Taylor, Cardiff University, shows the diffractometer in use there. He points out the component parts and explains how the apparatus works. Taylor then puts several masks into the apparatus and examines their diffraction patterns. Using a model of a salt crystal (NaCl) as well as animated diagrams, Stuart Freake explains why a crystal must be rotated for x-ray diffraction. He shows an x-ray oscillation camera, explains how it works and shows a piece of exposed x-ray film. Freake goes on to show, with the aid of models, what the transform of a three dimensional object looks like. Freake next explains and demonstrates, with the aid of models, the analogue method of determining actual crystal structure from a series of x-ray diffraction photographs. C.A. Taylor explains, with the aid of several models and diffraction patterns, how the molecular structure of hexa-Methyl-benzene might be derived by optical means. Taylor next shows an x-ray diffraction patterN of a man-made fibre and goes on to explain how its structure might be determined by the analogue method. Shots of pages from the "Atlas of Optical Transforms" and of optical analogue masks. Stuart Freake shows several masks and their diffraction patterns in order to demonstrate the effect of size and orientation of fibres on their diffraction patterns. Shots of an optical diffraction pattern of blue asbestos fibres in water. The pattern shows the fibres first in random array and then under the influence of a magnetic field. Freake sums up by pointing out one of the practical applications of this research.
Master spool number: HOU2330
Production number: 00525_1246
Videofinder number: 2117
Available to public: no