1. Bohr’d with Atoms?

Life is made of matter. And matter, for the most part, is made of atoms. There are exceptions to that latter statement, of course, but for our purposes this generalization is entirely acceptable. Atoms have undergone quite a metamorphosis since they were cooked up by the ancient Greek philosopher Democritus. In the last century or so, the atom has matured from a "plum pudding" model, in which negatively charged electrons were embedded like raisins in a positively charged goo, to the now-familiar and ubiquitous "solar system" atom, in which a massive nucleus consisting of positively charged protons and electrically neutral neutrons sits at the center and tiny electrons orbit the periphery like planets. This is more properly known as the Bohr model of the atom. The great Danish physicist Niels Bohr first formulated and used this model to attack certain fundamental problems in physics.