After James Chadwick discovered the neutron, atomic theory expanded to include isotopes. Isotopes have many practical uses. For example, scientists use the relative amount of carbon-12 to carbon-14 in ancient bones to determine how old they are.

James Chadwick, like Emest Rutherford, had to infer that neutrons were present in atoms. He made inferences based on observations of the
behavior of atoms during experimental tests. Using evidence from Rutherford's gold foil experiment, defend the following claim: Scientific
knowledge is based on observation and inference