Pioneers Flashcards
Ernest Rutherford: Background, achievements, other
Brusque, booming voiced New Zealander, b 1871.
Discovered, with his team, that atoms consisted mostly of empty space. Firing alpha particles through a very thin gold foil, they found about 1 in 8000 bounced back. Realised they were hitting the atom nuclei. A new model of the atom: the positive charge of an atom, and almost all of its mass, is concentrated in a ‘nucleus’, surrounded by a cloud of electrons.
“A gnat in the Albert Hall” although the gnat is thousands of times heavier than the building it occupies.
Niels Bohr: Background, discoveries, other
“The Great Dane”, founded the Copenhagen Institute in 1920. 1885-1962.
Proposed that electrons revolve in stable orbits around the nucleus but can jump from one energy level (or “orbit”) to another. Devised the notion of “complementarity” - aka wave-particle duality, at the heart of quantum mechanics.
He worked with the Danish authorities to smuggle all of Denmark’s 7000 Jews into Sweden.
Famous meeting in 1941 with Heisenberg, who had become head of the German nuclear weapon project.
Fled for Sweden in 1943, then Britain, in the bomb bay of an RAF Mosquito. Mediated between the British atomic scientists and America-based bomb team. Made several visits to Los Alamos.
Returned to Copenhagen after the war.
Wolfgang Pauli: Background, discoveries, other
1900-1958, born in Vienna. Scathing critic, friend of Bohr, Heisenberg and Jung (having consulted him after his divorce and mother’s suicide).
Discovered the “exclusion principle” for electrons, three can’t share the same orbit. Explains why they don’t collapse into the nucleus.
Became fascinated by the apparent gulf between psychology and science. Among the first physicists to worry deeply about the interplay between the material world outside of us and the mental universe within.
The Pauli effect was named after his anecdotal bizarre ability to break experimental equipment simply by being in its vicinity.
Dmitri Mendeleev: Background, discovery
Russian chemist. In 1869, worked out that certain properties of the elements, such as mass per unit volume and their chemical reaction, had a discernible pattern. Created a table that listed the atomic weights of the elements in rows and their shared chemical characteristics in columns. Only an initial 50 elements but arranged them correctly and the foresight to leave gaps for undiscovered elements. Never received a Nobel prize but element 101 was named Mendeleevium, Md, after him.
Werner Heisenberg: Background, discoveries, other
1901-1976. Born in Würzburg, Germany. Studied Plato.
Came up with the “uncertainty principle”: the more precisely the position of a particle is determined, the less precisely the momentum is known. The classical path of a particle comes into existence only when we observe it. The uncertainty principle was published in 1927; he was awarded the 1932 Nobel Prize in Physics “for the creation of quantum mechanics”.
Heisenberg admired Eastern philosophy and saw parallels with quantum mechanics.
Accused of working with Jewish scientists and believing the “Jewish science” of Einstein. Quizzed by the SS but his mother knew Heinrich Himmler’s mother and he was assured by Himmler that the personal attacks would end.
Returned to Germany from the US, resisting Fermi’s entreaties to stay, and headed the Nazi uranium fission project at the Kaiser Wilhelm Institute in Berlin.
Met with Bohr in 1941 in occupied Denmark; their recollections of the meeting differ.
After the war he claimed to have deliberately slowed the effort to build a bomb. He made some key errors and, a brilliant theorist, he lacked a good practical engineer. His neutrons were almost always too fast. He decided incorrectly that graphite was no good as a moderator. Turned instead to paraffin while waiting for water from “heavy” hydrogen from Norway.
Erwin Schrödinger: Background, discoveries, other
B Vienna 1887, d 1961. Adulterer and enthusiastic womaniser, restless, fled the Nazis. Had a deep interest in philosophy including the Upanishads and Advaita Vedanta’s interpretation.
His famous problem known as Schrödinger’s cat was actually meant to illustrate the absurdity of quantum mechanics by showing how uncertainty could impinge on what we think of as the real and everyday world. We couldn’t have subatomic particles that were neither one thing nor the other unless there were also things that were neither one thing nor the other.
A serial abuser and probable paedophile. Trinity College Dublin in 2022 removed his name from a lecture theatre that had been named for Schrödinger since the 1990s.
Paul Dirac: Background, discoveries, other?
Born in 1902 in England, grim childhood, shunned human company and worked in almost complete isolation.
Created a mathematical bridge between Schrodinger and Heisenberg’s description of the behaviour of electrons. His equation posited that there could be particles with opposite electrical charges, mirror images - anti-electrons or “positrons” with negative energy and negative mass: anti-matter. Subsequently first detected in cosmic rays in 1932. Positrons are used in medical imaging.
Dirac was known among his colleagues for his precise and taciturn nature. His colleagues in Cambridge jokingly defined a unit called a “dirac”, which was one word per hour. Modest.
Max Planck: Background, discoveries, other
Born in Kiel, 1858, grew up in the era of German unification under Otto van Bismarck. Died 1947.
He devised a mathematical equation to show energy was absorbed or emitted in discreet “bundles”: h or Planck’s Constant. He showed that energy is “lumpy” rather than Einstein’s smooth space-time Theory of Relativity. The key mismatch between this and quantum mechanics.
Met with Hitler in 1933 and pleaded with him not to persecute Jewish scientists. House destroyed and all his papers in a bombing raid in February 1944. His son, Erwin, executed for plotting to kill Hitler.
The pre-war Kaiser Wilhelm Institute in Berlin became the Max Planck Institute at the insistence of the British occupying forces and he became its president.
Marie Curie: Background, discoveries, other
Born in Poland, Maria Sklodowska, 1867. Entered the Sorbonne, one of the few universities that admitted women. Married Pierre.
Studied the rays given off by uranium and described them as “radio-actif”. Found other elements as well, including polonium and radium, that were much more radioactive. Joint Nobel prize then, after Pierre’s death, Marie was awarded another - the first woman to receive one.
She was known for her modesty and generosity.
During WW1, she dedicated herself to the cause of mobile x-ray units. Died in 1934 from leukemia, almost certainly brought on by years of exposure to radiation. In 1995 she became the first woman to be entombed on her own merits in the Paris Panthéon, alongside Pierre. Their remains were sealed in a lead lining because of the radioactivity.
Radium was used as a quack medicine and for illuminating the dials of watches. Factory workers - the “radium girls” - suffered appallingly. A factory in New Jersey poisoned to death more than 100.
Enrico Fermi: what breakthrough did he achieve and what did he unwittingly unleash?
Born in Rome in 1901. At the age of just 25 he became head of theoretical physics at the University of Rome.
At the same age he worked out why neutrons could penetrate substances much more deeply that alpha or beta particles - they swept past the usual blockages of positive charge from protons and negative charge from electrons. They could be used to “probe” atoms so long as they were slowed down so they didn’t push right through them.
By so doing, he announced he had transformed uranium atoms into new and heavier isotopes whose radioactivity decayed after just a few seconds into lighter nuclei. Without realising it, he had split some of the uranium atoms.
Won the Nobel prize and fled Mussolini’s Italy (his wife was Jewish) for the US, joining the Manhattan Project.
Commandeered an old squash court at Chicago University under the stand of the football stadium and built the world’s first nuclear reactor.
