J.J. Thomson was born #OTD in 1856. He discovered the electron, developed experimental techniques that led to mass spectroscopy, trained physicists like Rutherford and Bohr, but was ~betrayed~ by his own son in the ultimate act of filial physics rebellion.

(Okay, he wasn't exactly "betrayed" but bear with me.)

At the time of Thomson’s big discovery, most physicists were pretty sure that atoms were built out of much smaller components. But how could they prove this?

Thomson observed the way particles from a cathode ray tube were deflected by magnets and charged plates, and concluded that their charge-to-mass ratio must be relatively large. He estimated that they were at least 1,000 times less massive than atoms.

And their properties seemed to be independent of the type of atom from which they originated. Hence, a very light building block of atoms with a substantial (and negative) charge-to-mass ratio.

Many physicists were close to this discovery. But Thomson got there first, announcing his results on April 30, 1897. He referred to his particles as “corpuscles,” a name he’d use for several years.

But others dubbed the particle “electron,” a name coined by Irish physicist George Johnstone Stoney in 1891 for the fundamental unit of electric charge. (Stoney was the uncle of George Fitzgerald, who proposed length contraction to explain the null result of Michelson & Morley.)

Even though he insisted on using the name “corpuscles,” Thomson still received the 1906 Nobel Prize for his discovery.

Now, here’s the interesting twist.

Thomson’s son George also became a physicist. And George took an interest in de Broglie's 1924 hypothesis that matter should exhibit wavelike properties. https://twitter.com/mcnees/status/1294637386492719105

George then performed a diffraction experiment that confirmed de Broglie's hypothesis for electrons! This led to a Nobel Prize in 1937.

So Joseph John Thomson, the father, discovered the electron and regarded it as a particle. And George Thomson, the son, showed that his father’s particle experienced diffraction like a wave.

JJ: [beaming with pride] “How’s your research, my boy? I hear you’re studying my PARTICLE the electr –– what's all this then?”

George: [drops diffraction apparatus] “The electron is a WAVE, old man.” [storms out]

JJ: “To your room with you! You can come out when you’ve learned to respect the particle nature of matter.”

George: "I'm out of here." [flicks his cigarette and tunnels through the front door]