Characters in Rutherford's life
Ernest Marsden (1889-1970
As a young student in Manchester, Ernest Marsden played an important role, by a succession of coincidences, in establishing one of Ernest Rutherford's fundamental theories.
He would later become a major figure in science in New Zealand.
Pictures:
Ernest Marsden in Manchester in 1910. Source: Alexander Turnbull Library
Ernest Marsden receiving his diploma, Manchester 1909. Source: Royal Society of New Zealand Te Apārang
3D reconstruction of the device used by Geiger and Marsden ("gold leaf experiment") Source: Wikipedia
Simplified diagram of the experiment supplemented by a diagram of the trajectory of the alpha particles through the gold leaf. Source: Phylogamous
Ernest Marsden in 1921. Source: Wikipedia .
The first chance that changed Marsden's fate was a slight modification in an assembly used by Rutherford, who was then director of the physics laboratory at Victoria University of Manchester .
On a beautiful afternoon in 1908, the Prof, as several members of his team called him, indeed noticed that a prism had been moved in an installation he was using with Thomas Royds, another young researcher._cc781905- 5cde-3194-bb3b-136bad5cf58d_
Seeing this, Rutherford flew into his usual anger and looked for the culprit.
However, in the room he had just entered, there was only one person: Ernest Marsden, a 19-year-old student, busy with experiments related to phosphorescence (an easy subject, according to the habit of Rutherford to never give beginners research that is too complex, to avoid failure and frustration during their first months in his lab).
"Did you move that prism?" roared the Boss to the young researcher.
To which the reserved adolescent Ernest Marsden replied, unfazed by this hulking figure who was twice his age and occupied a place at the other end of the physics department's organizational chart from him: " No".
Not another word.
Rutherford stormed out of the room... and returned an hour later.
"Marsden, can I talk to you?"
- Yes.
— I found the culprit, added the boss of physicists.
He then pulled out a stool close to where his student was standing. He sat down heavily and spoke again in a surprisingly calm voice:
“I wanted to come and apologize for having called you into question, just now. I'm really sorry for letting myself go. I hope you won't hold it against me?
"No, Professor," the student stammered.
"Good," exclaimed Rutherford. What are you currently working on?
Marsden told him about his subject, the progress he was making, the difficulties he was encountering. Rutherford then asked him what his plans were: a thesis? a research career? a teaching job? in which university ?
They talked like this for more than two hours. Nothing else existed, not even their difference in age and situation.
The second serendipity in Ernest Marsden's life came the following year.
After working on the detection of alpha particles with Hans Geiger , Rutherford had let the latter continue research on the deflection of these same particles by different metals.
The Prof had added Ernest Marsden to him, thus following one of his principles which was to have a seasoned researcher collaborate with a beginner.
However, this beginner once explained to his boss an improvement he had made to avoid problems in the study of alphas: to be certain that the particles were not deflected by roughness present on the glass walls of their " particle cannon", Marsden had imagined placing circles perpendicular to the axis of the cannon, which could then stop the particles bouncing off these walls.
From this idea emitted by one of its youngest researchers arises an illumination of Rutherford. He then asked Marsden and Geiger to see if this phenomenon of "reflection of alphas" which occurred on glass could also occur with metal plates. This is how the famous gold leaf experiment was born. Which experiment required a lot of perseverance from Marsden and Geiger, a very long analysis from Rutherford and gave rise to the creation of Rutherford's atomic model.
Small clarification: this experiment could not have existed without a crucial innovation: the creation of a circular screen capable of rotating around the source of alpha particles, while maintaining a complete vacuum inside the installation. . Again, this was Marsden's idea.
(For more details, see the description of theRutherford-Geiger-Marsden experiment ).
At the beginning of the 1911 academic year, Ernest Marsden (22 years old) was appointed lecturer at the University of London.
In 1915, on the recommendation of Rutherford, Ernest Marsden was appointed professor of physics at Victoria College, Wellington, New Zealand (he did not take up his post until 1915, as his departure for the antipodes had been disrupted by the outbreak of the First World War).
Marsden spent his entire career in the native country of Rutherford, the man who had changed his life.
Sources :
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Giant of the atom: Ernest Rutherford, Robin McKown, page 97
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Rutherford, Scientist Supreme, John A. Campbell page 328
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Being the life and letters of Lord Rutherford, Arthur Stewart Eve, page 244
