The Manhattan Project: Witness to the Atomic Age

Abstract

In 1939, German physicist Lise Meitner and German chemist Otto Hahn proved for the first time that a sufficiently powerful ray of neutrons could split the atom. This, in turn, led physicists to begin to speculate about the feasibility of a new and terrible weapon—the atom bomb. Scientists knew that a powerful bomb might be possible, mainly because of Danish physicist Niels Bohr’s “liquid-drop” model of the atom. In Bohr’s model, published in 1939, the nucleus is a droplet made up of protons and neutrons. Bohr believed that because of the electrostatic repulsions between positively charged protons in the nucleus, tremendous energies were required to hold the nucleus together. Thus, based on purely theoretical considerations, they speculated that this energy, if it could be released, would constitute a tremendously powerful weapon.¹