J ob Chaula Niels Bohr’s World View

1. JobChaula Niels Bohr’s World View Niel Bohr 1885 -1962 Bohr's family fled to Sweden in a fishing boat when German army occupied Denmark Realism, Rationalism & Scientific Method By P.K. Feyerabend

2. Introduction • Niel Bohr was a Danish Physist (1885-1962). • His contributions • Significance of Quantum Theory • His ways of Treatment of Puzzles, History and refutations Realism, Rationalism & Scientific Method By P.K. Feyerabend

3. Bohr’s Contribution • Bohr made numerous contributions to our understanding of atomic structure • Bohr is considered to be one of the founders of quantum mechanics. Added new idea of quanta to the model put forth by Max Planck. That electrons existed at set levels of energy, that is, at fixed distances from the nucleus. His model made the theory fit the experimental evidence . Realism, Rationalism & Scientific Method By P.K. Feyerabend

4. Bohr’s Contribution • Complementarity Principal That things may have a dual nature (as the electron is both particle and wave) But we can only experience one aspect at a time. Realism, Rationalism & Scientific Method By P.K. Feyerabend

5. Bohr’s Contribution • correspondence principle A new, more general theory should dovetail with an older, more restricted theory. The two should generate the same results, under the ‘normal’ circumstances where The older theory remains a good approximation. Realism, Rationalism & Scientific Method By P.K. Feyerabend

6. Bohr’s Contribution • In 1920 founded the Institute for Theoretical Physics at the University of Copenhagen • Offered a place for many escaping Jewish scientists to live and work during II WW • He later donated his gold Nobel medal to the Finnish war effort. • He contributed to CERN, Europe's great particle accelerator and research station. Realism, Rationalism & Scientific Method By P.K. Feyerabend

7. Significance of Quantum Theory • New fields in physics emerged:condensed matter physics, superconductivity, nuclear physics, and elementary particle physics—that all found a consistent basis in quantum mechanics • Enhanced the understanding of the structure of matter • The understanding of chemical bonding Realism, Rationalism & Scientific Method By P.K. Feyerabend

8. Bohr’s Treatment of Puzzles • Should not only be assimilated to old paradigm but • Should be turned into fundamental difficulties by looking at them from a new direction and • By testing their background Realism, Rationalism & Scientific Method By P.K. Feyerabend

9. Bohr’s Considerations of History • His papers are heavily seasoned with historical material • Are characterized as preliminary summaries surveying the past • giving account of present state of knowledge and making general suggestions, in the spirit of correspondence principal on the possible course of research • Early Einstein papers lack this important component of history. Realism, Rationalism & Scientific Method By P.K. Feyerabend

10. Bohr’s View of Refutation • He generalized Einstein’s considerations and published a purely statistical particle theory with waves acting as probability field only. …..This theory was refuted….. • He considered “Refutation” and “Success” to be part of progress • Realized the need to retain the sense of perspective even in surprising successes and failures! Realism, Rationalism & Scientific Method By P.K. Feyerabend

11. Never Express Yourself more clearly Than you can think Realism, Rationalism & Scientific Method By P.K. Feyerabend

12. Questions ? Realism, Rationalism & Scientific Method By P.K. Feyerabend