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Kinetic Theory

Melvyn Bragg and guests discuss the growth of ideas about gas pressure, from Newton's theory that static particles push against each other to Maxwell and Boltzmann's moving atoms.

Melvyn Bragg and guests discuss how scientists sought to understand the properties of gases and the relationship between pressure and volume, and what that search unlocked. Newton theorised that there were static particles in gases that pushed against each other all the harder when volume decreased, hence the increase in pressure. Those who argued that molecules moved, and hit each other, were discredited until James Maxwell and Ludwig Boltzmann used statistics to support this kinetic theory. Ideas about atoms developed in tandem with this, and it came as a surprise to scientists in C20th that the molecules underpinning the theory actually existed and were not simply thought experiments.

The image above is of Ludwig Boltzmann from a lithograph by Rudolf Fenzl, 1898


Steven Bramwell
Professor of Physics at University College London

Isobel Falconer
Reader in History of Mathematics at the University of St Andrews


Ted Forgan
Emeritus Professor of Physics at the University of Birmingham

Producer: Simon Tillotson

Available now

52 minutes

Last on

Thu 23 May 2019 21:30


Steven Bramwell at University College London

Isobel Falconer at the University of St Andrews

Ted Forgan at the University of Birmingham

‘History of the Kinetic Theory of Gases’ by Stephen Brush

Kinetic theory of gases – Wikipedia



Stephen G. Brush, The Kinetic Theory of Gases: An Anthology of Classic Papers with Historical Commentary (Imperial College Press, 2003)

Brian Clegg, Professor Maxwell’s Duplicitous Demon (Icon Books, 2019)

Carlo Cercignani, Ludwig Boltzmann: The Man Who Trusted Atoms (Oxford University Press, 2006)

Olivier Darrigol, Atoms, Mechanics, and Probability: Ludwig Boltzmann’s Statistico-Mechanical Writings - An Exegesis (Oxford University Press, 2018)

Richard Feynman, Robert Leighton and Matthew Sands, The Feynman lectures on Physics: Vol I (Basic Books, 2011), especially chapters 39-43

Raymond Flood, Mark McCartney, and Andrew Whitaker (eds.), James Clerk Maxwell: Perspectives on His Life and Work (Oxford University Press, 2014)

Gerald Holton and Stephen G. Brush, Physics, the Human Adventure: From Copernicus to Einstein and Beyond (Rutgers University Press, 2001)

Oded Kafri and Ḥaṿa Kafri, Entropy: God’s Dice Game (CreateSpace, 2013)

Keith J. Ladler, The World of Physical Chemistry (Oxford University Press, 1995)

David Lindley, Boltzmann’s Atom: The Great Debate That Launched A Revolution in Physics (Free Press, 2016)

Basil Mahon, The Man Who Changed Everything: The Life of James Clerk Maxwell (John Wiley & Sons, 2004)

Abraham Pais, Subtle is the Lord: The Science and Life of Albert Einstein (Oxford University Press, 2005)

Theodore M. Porter, The Rise of Statistical Thinking, 1820-1900 (Princeton University Press, 1986)



  • Thu 23 May 2019 09:00
  • Thu 23 May 2019 21:30

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