Melvyn Bragg and guests explore the history of physics through its most important ideas and hypotheses

Eclectic, erudite and entertaining, In Our Time is one of Radio 4's most successful programmes, regularly attracting an audience of over 2 million for its discussions on every subject under the sun: from oceanography to Ovid.

In this special themed collection, Melvyn Bragg is joined by guest experts including Simon Schaffer, John Gribbin, Jim Al-Khalili and Sir Martin Rees to discuss 25 of the key laws, principles and problems of physics. Here are examinations of major concepts including plasma, radiation, matter and antimatter and the Second Law of Thermodynamics, as well as discourses on historical theories such as Zeno's paradoxes, the speed of light and relativity. Also featured are analyses of modern developments in physics, including the discovery and growing understanding of the proton, neutron and electron, the controversial breakthrough of nuclear technology, and the search for the holy grail of 20th century physics: the Grand Unified Theory.

Physicists, students of science and knowledge seekers will savour these wide-ranging, comprehensive and accessible discussions, which serve as a springboard to dive deeper into the fascinating fundamental principles that govern our universe.

Production credits
Presented by Melvyn Bragg
Produced by Thomas Morris and Simon Tillotson

First broadcast on BBC Radio 4 on the following dates:

Part I: Major Concepts
States of Matter 3 April 2014
Heat 4 December 2008
Absolute Zero 7 March 2013
The Second Law of Thermodynamics 16 December 2004
Plasma 13 October 2016
Magnetism 29 September 2005
Radiation 12 November 2009
The Physics of Time 18 December 2008
Quantum Gravity 22 February 2001
Antimatter 4 October 2007
The Graviton 24 November 2005
Optics 1 March 2007
With Simon Schaffer, Jim Bennett and Emily Winterburn

Part II: Historical Theories
Zeno's Paradoxes 22 September 2016
The Speed of Light 30 November 2006
The Laws of Motion 3 April 2008
Kinetic Theory 23 May 2019
Relativity 6 June 2013
The Physics of Reality 2 May 2002

Part III: Modern physics
Grand Unified Theory 24 February 2000
The Electron 29 September 2022
Nuclear Physics 10 January 2002
Cosmic Rays 16 May 2013
The Proton 26 April 2018
The Neutron 14 April 2016
The Neutrino 14 April 2011