- Why was distinguishing alpha from beta radiation a necessary step toward understanding nuclear decay?
Nuclear Physics
The structure, reactions, and decay of atomic nuclei.
- What led Rutherford to predict the existence of a neutral nuclear particle years before Chadwick confirmed the neutron?
- Why would a neutral particle be immune to the Coulomb repulsion that made packing protons together difficult?
- How many years passed between Rutherford's prediction of the neutron and Chadwick's experimental discovery of it?
- Why did the observed scattering angles of alpha particles off hydrogen nuclei deviate from what the Coulomb law predicted?
- What did Chadwick and Biéler conclude about forces between charged particles at very short distances?
- How long did it take for the strong nuclear force implied by this scattering data to be formally theorized?
- What is the whole-number rule, and what did its small deviations turn out to signify?
- How did Aston's isotope measurements foreshadow the discovery of nuclear energy?
- Why did Rutherford predict as early as 1920 that the nucleus must contain a neutral particle?
- How did the energy balance of ejected protons reveal that a neutral, proton-mass particle was responsible?
- What role did Urey's discovery of deuterium end up playing in the development of nuclear weapons?
- Why did Fermi switch from alpha particles to neutrons when bombarding elements in his Rome laboratory?
- Why can a neutron enter an atomic nucleus more easily than a proton can?
- Why did the Nobel committee wait three years to recognize Chadwick's discovery?
- Why did slowing down neutrons with paraffin or water make them more effective at triggering nuclear reactions?
- Why was the presence of barium in neutron-bombarded uranium so inexplicable under the physics of 1938?
- How did Lise Meitner and Otto Robert Frisch use the liquid-drop model to explain the appearance of barium?
- How does the molecular beam magnetic resonance method reveal the magnetic moment of an atomic nucleus?
- Why did Rabi's precise measurements of nuclear spin matter for testing quantum theory in the 1930s?
- What problem did Yukawa's predicted particle solve about the force holding the nucleus together?
- How did the energy released by the split lithium nucleus confirm Einstein's mass-energy equation?
- What is parity, and why had physicists assumed it held for every force in nature?
- How did Robert Hofstadter use electron scattering to show that protons and neutrons have an internal charge distribution rather than being point particles?
- What did Hofstadter's measurements of nuclear size and structure open up for later nuclear physics research?
- What are 'magic numbers' in nuclear physics and why do they make certain nuclei unusually stable?
- How did Maria Goeppert Mayer's spin-orbit coupling term change the nuclear shell model?
- What role did symmetry principles from group theory play in Eugene Wigner's contribution to nuclear physics?
- How does the nuclear shell model apply to the modern search for superheavy elements?
- Why did physicists originally assume atomic nuclei were spherical?
- How can outer nucleons deform a nucleus into an elongated shape?
- What practical fields depend on the collective model of the nucleus today?
- What was it like for Aage Bohr to win a Nobel in the same field as his father Niels?
- Why would Kervran's theory of biological transmutation contradict established nuclear physics?
- What is neutron spectroscopy measuring that neutron diffraction alone cannot?
- Why did the strong nuclear force resist mathematical description for so long?
- What did Yang and Lee argue in 1956 about parity conservation in the weak nuclear force that no one had tested?