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This programme features experiments filmed at a high energy laboratory near Paris and a cosmic ray field station on the Yorkshire moors. In addition, considerable use is made of graphics animation investigate the nature of time in examples used by Einstein to explain the prediction that a moving clock runs slow. Time for all moving things is dilated, spread out, in relation to a fixed observer. The speed of light is measured first from a fixed source (a flash light mounted 3 metres from a detector), then from a source moving very rapidly (a beam of electrons travelling close to 3 x 10₈ metres/sec). No difference at all is found, this supporting Einsteins assumption that in the velocity of light we have a truly universal constant. This leads to the prediction that for very fast moving "clocks", time runs slow relative to a non-moving observer's "clock". This prediction is tested experimentally by comparing the rates of 'muon' particles travelling very fast towards the earth from high up in the atmosphere; on the Earth and at an altitude of 4,500 ft. This was filmed using a helicopter directly above the Muon ground station in Yorkshire. It is thought that this is the first time this experiment has been carried out (and filmed) - the results showed that time for these muons is running at least three times slower than for muons created in the laboratory effectively at rest. The speakers are Dr. Bob Lambourne (OU), Dr. Alan Cooper (0U), Dr. Allan Solomon (OU) and Professor Russell Stannard (OU).
Metadata describing this Open University video programme
Module code and title: S271, Discovering physics
Item code: S271; 12
First transmission date: 04-08-1982
Published: 1982
Rights Statement:
Restrictions on use:
Duration: 00:24:00
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Producer: Tony Jolly
Contributors: Alan Cooper; Bob Lambourne; Allan I.,1936-2013 Solomon; Russell Stannard
Publisher: BBC Open University
Keyword(s): Animations; Clocks; Cosmic ray; Einstein; Inertial frames; Muons; Paris; Relativity; Time; Yorkshire moors
Production number: FOUS251D
Videofinder number: 1791
Available to public: no