Douglas Butler illustrates how to create an Autograph file to test the parabolicality of a sound mirror, at the Association of Teachers of Mathematics website.
Archive for the ‘Technology’ Category
Talking parabolicality
Sunday, August 30th, 2009Boffins in Britain
Sunday, August 23rd, 2009Alec Muffett at Dropsafe on sound mirrors.
Britain is a hothouse of brains and creativity, doubly-so for having to make-do-and-mend from underinvesment and underappreciation, and this leads to startling solutions that fuel incredible innovation - even if most of those subsequently flop for lack of business nous.
Occasionally, these innovations leave footprints in the sand. Bletchley Park is onesuch. Another of which I have long known a little, but never known a lot, are the sound mirrors.
Parabolic sound mirrors to reflect and focus sound
Friday, April 10th, 2009The Whipple Museum of the History of Science in Cambridge has a webpage about some parabolic sound mirrors to reflect and focus sound.
This apparatus consists of a pair of brass parabolic reflectors mounted on wooden stands. One of the reflectors has a bracket with a hook for hanging a pocket watch. The demonstrator would use this apparatus to show how the sound of a ticking watch may be heard at a considerable distance having first been made into a beam, projected over a distance and refocused. Very little is known about this pair of mirrors in the Whipple’s collection. It is thought that they were made in France or Germany during the second quarter of the nineteenth century.
Source: Whipple Museum of the History of Science
