Conductors and Semiconductors

In Our Time

BBC

History

4.6 • 9.2K Ratings

🗓️ 23 February 2012

⏱️ 43 minutes

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Summary

Melvyn Bragg and his guests discuss the physics of electrical conduction. Although electricity has been known for several hundred years, it was only in the early twentieth century that physicists first satisfactorily explained the phenomenon. Electric current is the passage of charged particles through a medium - but a material will only conduct electricity if its atomic structure enables it to do so. In investigating electrical conduction scientists discovered two new classes of material. Semiconductors, first exploited commercially in the 1950s, have given us the transistor, the solar cell and the silicon chip, and have revolutionised telecommunications. And superconductors, remarkable materials first observed in 1911, are used in medical imaging and at the Large Hadron Collider in Geneva. With:Frank CloseProfessor of Physics at the University of OxfordJenny NelsonProfessor of Physics at Imperial College LondonLesley CohenProfessor of Solid State Physics at Imperial College LondonProducer: Thomas Morris.

Transcript

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0:00.0	Just before this BBC podcast gets underway, here's something you may not know.
0:04.7	My name's Linda Davies and I Commission Podcasts for BBC Sounds.
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0:36.0	Thanks for downloading the In Our Time Podcast. For more details about In Our Time and for our terms of use, please go to BBC.co. UK forward slash radio for
0:45.3	I hope you enjoy the program.
0:48.0	Hello until the end of the 19th century the phenomenon of electricity was very poorly understood, but in a few generations
0:55.5	the world was transformed, first by electric power and then by the electronic revolution,
1:00.6	which resulted in invention of computer technology.
1:04.1	The transformation was brought about by a new understanding of not just of electricity, but
1:08.8	of the materials through which it can travel.
1:11.4	All substances on the planet can be divided into categories according to their ability to conduct
1:16.3	electricity. Those that can, like metals, are called conductors. Those that don't are known
1:20.9	as insulators. But there are also semiconductors whose discovery has made
1:24.8	possible the invention of the transistor and the solar cell. And finally, there are
1:28.8	superconductors whose unique properties have a range of useful applications from medical imaging to
1:34.0	particle accelerators.
1:35.7	With me to discuss electrical conduction, semiconductors and superconductors, a Frank Close,
1:40.8	professor of physics at the University of Oxford, Jenny Nelson, Professor of Physics
1:45.2	at Imperial College London, and Leslie Cohen, Professor of Solid State Physics also of Imperial
	...

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