- What later applications did radium's isolation make possible?
Nuclear Fission
The splitting of heavy atomic nuclei and its applications.
- What later technologies and phenomena trace their understanding back to this mass-energy equivalence?
- What later discoveries about splitting the nucleus trace back to Rutherford's 1911 model of the atom?
- What happened when Rutherford fired alpha particles at nitrogen gas that he didn't originally expect?
- How did nitrogen become oxygen in Rutherford's experiment?
- What made this the first artificially induced nuclear reaction in history?
- How did firing alpha particles at nitrogen gas produce hydrogen nuclei in Rutherford's experiment?
- What did Rutherford's conversion of nitrogen into oxygen prove about the structure of atomic nuclei?
- Why is Rutherford's 1917 experiment considered the first deliberately engineered nuclear reaction?
- How did bombarding nitrogen gas with alpha particles allow Rutherford to eject and identify the proton?
- How did the discovery of the neutron eventually make nuclear fission possible?
- What device did Cockcroft and Walton build to accelerate protons to high enough voltage to split a nucleus?
- What happened to a lithium-7 nucleus when it captured a proton in the 1932 experiment?
- How did the energy released by the split lithium nucleus confirm Einstein's E=mc² with direct measurement?
- Why did Cockcroft and Walton wait nearly two decades, until 1951, to receive their Nobel Prize?
- What did the Joliot-Curies observe that revealed radioactivity could be artificially induced rather than only found in nature?
- Why did aluminium, boron, and magnesium keep emitting positrons even after the polonium source was removed?
- Why did Fermi switch from alpha particles to neutrons when bombarding elements in his Rome laboratory?
- What did Fermi's team mistakenly conclude they had created when they bombarded uranium with neutrons?
- How did Lise Meitner and Otto Frisch later show that Fermi had actually achieved nuclear fission in 1934?
- How did bombarding beryllium with alpha particles reveal a new subatomic particle?
- What later technologies depended on the discovery of the neutron?
- How did the Joliot-Curies produce radioactive isotopes that don't occur in nature?
- What is the difference between observing radioactivity and being able to induce it?
- What fields eventually relied on artificially produced radioisotopes?
- What insight did Szilard have while crossing a London street in 1933?
- Why did Szilard patent the chain reaction concept and then assign it to the British Admiralty?
- How does a single neutron striking a nucleus lead to a runaway multiplication of reactions?
- How did the Joliot-Curies' work on synthetic radioisotopes enable this medical application?
- How did Fermi's slow-neutron findings become foundational to the design of the first nuclear reactor?
- What allowed Fermi to leave Fascist Italy permanently under the guise of attending his own Nobel ceremony?
- Why was the presence of barium in neutron-bombarded uranium so inexplicable under the physics of 1938?
- How did Lise Meitner and Otto Frisch work out that Hahn's results meant the uranium nucleus had split?
- Why did Otto Hahn alone receive the Nobel Prize for fission despite Meitner's essential contribution?
- What result did Otto Hahn get from bombarding uranium with neutrons that made no chemical sense at the time?
- How did Lise Meitner and Otto Robert Frisch use the liquid-drop model to explain the appearance of barium?
- Why does splitting a uranium nucleus release so much energy despite the mass deficit being tiny?
- Why was Lise Meitner excluded from the 1944 Nobel Prize awarded for the discovery of fission?
- When did Leó Szilárd first conceive of the nuclear chain reaction, and what prompted the idea?
- How did bombarding uranium-238 with deuterons in a cyclotron produce a brand-new element?
- Why does plutonium fission more readily under slow neutrons than uranium-235 does?
- Why was a disused squash court under Stagg Field chosen as the site for the first nuclear reactor?
- How did the control rods let Fermi start and stop a self-sustaining chain reaction on demand?
- What did the coded telegram 'the Italian navigator has landed in the new world' actually report to Washington?
- What did Hahn and Strassmann find when they bombarded uranium with slow neutrons that made no chemical sense at first?
- How did Lise Meitner, working in exile, supply the physics explanation for Hahn's puzzling barium result?
- Why was Meitner excluded from the 1944 Nobel Prize despite her role in explaining fission?
- Where and how did Otto Hahn learn he had won the Nobel Prize, and what else happened during that same internment?
- What new kinds of events did Blackett's coincidence-triggered chamber let him track?
- How did Cockcroft and Walton's accelerator split a lithium nucleus using a beam of protons?
- How did Edwin McMillan discover neptunium by bombarding uranium with neutrons?
- What did Fermi achieve beneath the bleachers of Stagg Field in December 1942, and why did that require assembling uranium and graphite by hand?
- Why did Fermi leave Italy in 1938, and how did the timing of his departure connect to his Nobel Prize?
- What made Fermi's colleagues coin his name as a category for a certain kind of physicist?
- What is a branched chain reaction, and how does it differ from a simple chain reaction?
- Why does a branching ratio determine whether a reaction burns steadily or detonates?
- How did Semenov in Leningrad and Hinshelwood in Oxford arrive at the same mechanism independently?
- What practical fields depend on the collective model of the nucleus today?
- How did a delay in the test and an unbriefed night shift contribute to the reactor becoming unstable?
- What did Gurdon's 1962 frog nucleus transplant prove about whether cell differentiation is reversible?