In the paper ‘What can the Bohr–Sommerfeld model show students of chemistry in the 21st century?’ (M. Niaz and L. Cardellini, J. Chem. Educ., 2011, 88, 240) the authors use the development of models of atomic structure to deliberate on the nature of science. What were the shortcomings of the Bohr model of the atom? How did Sommerfeld refine Bohr’s model? How did Pauli resolve some of the new model’s shortcomings? Discuss what these developments teach us about the nature of science.