The impact of the advances in physics between 1900 and 1938 could have never been predicted at the time of their discovery. The discoveries being made would change not only the world of physics, but also the world as a whole. Because developments were being made in the fields of fission, atoms, and atomic energy, government officials now had to take into consideration the possibility of atomic warfare when making related to international policy.
The first of the major world powers to realize the military use of the discoveries in physics was Germany. Soon after, the United States and Britain would begin organizing research teams in the field of fission and nuclear warfare. The fates of these research projects were constantly in question. The decision by Germany, the United States, and Britain to continue research would be influenced by many factors including the progress of other countries research, each countrys confidence in their ability to complete the atomic bomb, and each countrys confidence in the inability of other countries to produce the atomic bomb. The discovery of fission, in December of 19381, would begin the worlds quest to unleash the power of the atom and formulate a way to utilize that power for atomic warfare. This discovery, made in Germany, gave the Germans a head start on the extensive research still to be done in order to produce an atomic bomb.
This advantage would soon prove to be short lived. While this discovery overwhelmed the physics world with amazement, it also caused great concern among many physicists and government officials because of the implications in atomic warfare it held. This fear would become the most basic reason for the United States and Britain to pursue atomic research, particularly for military use. Germany was unaware of not only the pressure they were exuding, in the form of fear, on other countries, but also the research that was beginning out of this fear.
Germanys ignorance of this research allowed the German research project to continue at the same rate and escape feeling pressure from other countries2. Without pressure from other countries Germany had a false sense of security, which allowed the urgent need to begin research to be ignored. For many years the best physicists and scientists studied and trained in Germany, because of its unrivalled reputation as the best location for scientific education and training available3. After completing their education many scientists chose to remain in Germany doing research or teaching. Prior to 1933 this would have provided Germany with an invaluable resource of information and ideas, but the increasing anti-Semitic attitude in Germany forced many scientists to flee the country. Among the refugees escaping Hitlers anti-Semitism were some of the most crucial contributors to the development of the atomic bomb, such as Albert Einstein and Leo Szilard4.
Leo Slizard fled from Germany on March 31, 19335, at which time he went to Britain where he conceived his neuron chain reaction. Slizard continued his research at Oxford in Britain until 1938 at which time he moved to New York City in anticipation and fear of the outbreak of World War II6. Upon moving to New York Slizard and Eugene Wigner began work on plans to avert attainment of an atomic bomb by Germany. In 1939 Slizard and Wigner approached Einstein to help warn the US of the threat posed by Germany. Slizard drafted Einsteins letter to President Franklin D. Roosevelt expressing their fear and knowledge of the German Uranium project7.
The letter to Roosevelt was powerful enough to convince the US to organize their research on the atomic bomb. While the research in the US was making constant progress, including Rudolf Peierls calculation of the critical mass in Dec. 1940, and Alfred Niers successful separations of natural uranium into U238 and U235 8, the Germans were facing a great deal of frustration. In 1941 Heisenberg reported negative results from his first experiments using a reactor, which caused him to conclude that heavy water must be used9. This premature conclusion would affect the progress and fate of the Uranium project. The next set back came in September of 1941 when the previously favored Clusius-Dickel isotope-separation method was abandoned due it becoming thought .