What His Experiment Was:

In1930, Walther Bothe and Herbert Becker experiment was: “bombarded beryllium with alpha particles emitted from the radioactive element polonium, and they found that the beryllium gave off an unusual, electrically neutral radiation.” They thought this radiation was from photons.

Not believing this, James Chadwick tried these experiments out for himself.

“What really occurred when one bombarded beryllium with alpha particles, Chadwick explained, was the formation of a carbon-12 nucleus and the emission of a neutron. Formation of a carbon-13 nucleus with the emission of a photon, as the Joliot-Curies had discovered, could not provide sufficient energy for the scattering pattern and energies of ejected particles from Chadwick’s various targets.” Thus, the neutron was formed.

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Fun fact: James Chadwick was from the United Kingdom.