CHAPTER 12: The Danes Jump in: Ørsted and Bohr (Denmark)

Hans Christian Ørsted discovered electromagnetism in 1820. We visit Ørsted sites on the island of Langeland, his birthplace, and in Copenhagen where plaques and statues celebrate his life and discovery. Niels Bohr is one of the most famous names in the development of the atomic concept. After earning his PhD at the University of Copenhagen in 1911, he went to England where he worked with J. J. Thomson and Ernest Rutherford. In the Bohr–Rutherford atom, he boldly asserted that classical laws are not valid inside the atom and needed to be replaced with the quantum ideas of Planck and Einstein. After explaining his theory and how it was received by his peers, we explore the many Bohr sites in Copenhagen including his birthplace, childhood home, and the Bohr family graves in the cemetery where Ørsted, Hans Christian Andersen, and Soren Kirkegard are also buried. When we finally visit the Niels Bohr Institute, we more fully appreciate his extraordinary influence on the physics of his time. At the end of the chapter, we briefly discuss two famous Danish astronomers, Tycho Brahe and Ole Rømer, and describe some relevant sites that celebrate their lives and work.