CHAPTER 15: Quantum Mechanics Reluctantly Proposed: Planck and Einstein (Germany and Switzerland)

This chapter describes the work of Max Planck and Albert Einstein, who were the first to propose the new “quantum ideas” that Niels Bohr used in his atom. In 1900, Planck reluctantly proposed that light energy comes in discrete lumps called “quanta”, given by his equation, E = hν. Einstein, in his annus mirabilis of 1905 proposed that there are times when light cannot be described as an electromagnetic wave but rather as a stream of particles called photons. He used this particulate model of light to explain the photoelectric effect. We recall the tragedies and triumphs of Planck's life when, in Berlin and Göttingen, we visit his residences, honorary statues and plaques, the Archives of the Max Planck Society, and his simple grave amongst those of seven other Nobel Laureates. We briefly describe Einstein's early years, his education in Zurich, his marriage to Mileva Marić, the birth of their first son Hans and then go on to visit multiple sites in Ulm, Munich, Berlin, Bern, and Zurich where his life is celebrated with plaques, monuments, statues, elaborate church windows, museums and in the flat where he and Mileva lived during the most productive time of his life.