The atomic bomb killed many innocent people, but it was necessary to end World War II. After World War II began in 1939, President Franklin Delano Roosevelt announced the neutrality of the United States. Many people in the United States thought that their country should stay out of the war. The people wanted the Allied Forces to have the victory. President Roosevelt also wanted an Allied victory because an Axis victory might endanger democracies everywhere. The United States equipped nations fighting the Axis with ships, tanks, aircraft, and other war materials. The Axis did not like this. Japan wanted to take over China, but China refused. China was led by Chiang Kai-Shek at the time. Japan wanted the United States to stop sending China supplies, but the United States refused. The United States opposed the expansion of Japan in Asia, so they cut off important exports to Japan. General Hideki Tojo was the Premiere of Japan. He and other Japanese leaders did not like the fact that Americans were sending war supplies to China and other countries in Asia. A surprise attack was ordered by Japan on December 7, 1941. The target was the U.S. naval base at Pearl Harbor, Hawaii. 360 planes bombed the naval base killing about 3,000 people and destroying many warships, aircraft carriers, and submarines. This was a catalyst that brought the United States into World War II.Albert Einstein predicted that mass could be converted into energy early in the century and was confirmed experimentally by John D. Cockcroft and Ernest Walton in 1932. In 1939, Otto Hahn and Fritz Strassmann discovered that neutrons striking the element uranium caused the atoms to split apart. Physicists found out that among the pieces of a split atom were newly produced neutrons. These might encounter other uranium nuclei, caused them to split, and start a chain reaction. If the chain reaction were limited to a moderate pace, a new source of energy could be th...
