The electron, the atom, the DNA and the Old Cavendish

I present this post about the Cavendish Laboratory because it was there where JJ Thomson discovered the electron. Until 2008 approximately, the Old Cavendish housed the High-Resolution Electron Microscopy Group that is part of the Department of Material Science and Metallurgy of the University of Cambridge (United Kingdom). Was it not the best place to have an electron microscopy facility?.

The history of the Cavendish laboratory is a long one since it was set up in the mid-XIX century as a place for experimental physics or “practical physics”.

The systematic teaching of practical physics is a modern development. Until the second half of the nineteenth century was well begun, no teaching laboratory and no regular course of instruction were known.


Cavendish, Cambridge, Free School Lane

Old Cavendish from Free School Lane

Then the Cavendish was founded and became an epicenter for fundamental scientific discoveries that paved the road how modern labs should be.  Since 1895, 29 Nobel Prizes have been awarded to scientists that worked in the Cavendish Laboratory. Not only in Physics but also in chemistry, medicine or physiology. In fact one of the most important scientific discoveries of the XX century, i.e., the DNA structure was made in the realms of the Old Cavendish.





The first Professor of the Cavendish was James Clerk Maxwell and after him a long list of distinguished scientists led the laboratory originally under the title of Cavendish Professorship of Experimental Physics. Until 1971 the list of names illustrious people included:

  • Lord Rayleigh (John William Sttrut) (1879-1884), discovered Argon, contributed to the discovery of surface waves, and provided insights into the phenomena of scattering.
  • J. J. Thomson (1884-1919) discovered the electron (charge/mass ratio) using a vacuum tube with mutually perpendicular magnetic and electric field, and a phosphor screen. Much like a modern electron microscope or a mass spectrometer. A blueplaque on a wall outside the Old Cavendish in Free school Lane remembers this event.
JJ Thomson, electron, Old Cavendish

Blueplaque outisde the Old Cavendish











  • Lord Rutherford (Ernest Rutherford) (1919-1937). Also know as the father of nuclear physics. Under his leadership the structure of the atom was confirmed. Check next video trailer showing snippets of a documentary on Ernest Rutherford. Directed by Gillian Ashurst, produced by Spacegirl Productions and John Campbell.

NOTE: The three part documentary (1 hour per part) is available for purchase on DVD from a web page dedicated to Rutherford.

He was joint winner (with his father, William Henry Bragg) of the Nobel Prize in Physics in 1915: “For their services in the analysis of crystal structure by means of X-ray , i.e., the beginning of crystallography using radiation.

  • Nevill Mott (1954-1971), considered one of the fathers of solid state physics.

In 1977, Nevill Mott was awarded the Nobel Prize in Physics, together with Philip Warren Anderson and John Hasbrouck Van Vleck “for their fundamental theoretical investigations of the electronic structure of magnetic and disordered systems.”

Pictures below correspond respectively to Maxwell, Rayleigh, Thomson, Rutherford, WL Bragg and Mott.


jj_tubeERutherford LBragg NMott























I want to recommend two books (see photograph at the top of this post) that are accounts about two of these discoveries carried out in the Cavendish: the split of the atom and the discovery of DNA. For completeness of the latter, check also this video in which the role that Rosalind Franklin played in this monumental discovery with her work on crystallography of DNA is mentioned. Her name has been at the center of one of the most polemic debates about science, ego and the understimated role of women in science.


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