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Assessing the Decision to Build and Use the Atomic Bomb

Assessing the Decision to Build and Use the Atomic Bomb

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Assessing the Decision to Build and Use the Atomic Bomb

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  1. Assessing the Decision to Build and Use the Atomic Bomb Col. Paul W. Tibbets, Jr., pilot of the Enola Gay, the plane that dropped the atomic bomb on Hiroshima, waves from his cockpit before takeoff.

  2. Albert Einstein

  3. Whether to Build an Atomic Bomb In August 1939, FDR received a letter from Albert Einstein. He alerted FDR that Germany might be building an atomic bomb. When Einstein wrote this letter to Roosevelt, the US was not yet at war with Germany. However, FDR took interest in the developments described in the letter. The bomb would not only be the most powerful weapon on earth, it would transform warfare by making it possible to kill more people with less effort.

  4. In the 18 months following Einstein’s letter, members of the Roosevelt administration debated what action should be taken to counter the German threat. Some officials wondered how serious the threat really was. In addition, not all scientists agreed with Einstein. In fact, two Nobel Prize-winning nuclear physicists, Enrico Fermi and Niels Bohr, believed that the construction of an atomic bomb was a practical improbability.

  5. Critical Thinking Question 1 You are an advisor to President Roosevelt. Which of the following do you advise the president to do? Explain why.

  6. A:Ignore scientific developments and do not build an atomic bomb; concentrate U.S. efforts on building conventional weapons, such as faster planes and more powerful tanks.

  7. B:Vigorously pursue the construction of an atomic bomb because the United States is in a race against the Germans.

  8. C: Postpone the development of an atomic bomb and send spies into Germany to determine the accuracy of Einstein’s letter.

  9. D: Do not develop the bomb. Instead, monitor the construction of new German weapon facilities and then send American bombers to destroy them.

  10. E: Denounce the development of atomic bombs as immoral. Only evil could come from their development.

  11. Question 1: Actual Decision • 1939 – FDR supported bomb research; discovered a bomb could be built in two years • Manhattan Project – code name for top secret project – Led by Robert Oppenheimer – 100,000 people involved – cost $2 billion – Fermi and Bohr major players in development • No formal agreement; just understood that any weapon developed would be used to end war quickly

  12. J. Robert Oppenheimer

  13. How the Bomb Worked A sphere of U-235 is made around the neutron generator and a small bullet of U-235 is removed. The bullet is placed at the one end of a long tube with explosives behind it, while the sphere is placed at the other end. A barometric-pressure sensor determines the appropriate altitude for detonation and triggers the following sequence of events: • The explosives fire and propel the bullet down the barrel. • The bullet strikes the sphere and generator, initiating the fission reaction. • The fission reaction begins. • The bomb explodes. Simulation: How the “Little Boy” bomb worked http://people.howstuffworks.com/nuclear-bomb5.htm

  14. How the Bomb Worked, Con’t. Scientists recognized that compressing the subcritical masses together into a sphere might be a good way to make a supercritical mass. There were problems with this idea. But the Manhattan Project team solved the problems. When the bomb was detonated, this is what happened: 1. The explosives fired, creating a shock wave. 2. The shock wave compressed the core. 3. The fission reaction began. 4. The bomb exploded. Simulation: How the “Fat Man” bomb worked http://people.howstuffworks.com/nuclear-bomb6.htm

  15. Workers with the Manhattan Engineer District gently carry the plutonium core for the world's first atomic bomb into the McDonald Ranch house for assembly, July 12, 1945

  16. A member of the Manhattan Project's Special Engineering Detachment holds the assembled plutonium core for the world's first atomic bomb in a special shock-absorbing case on July 12, 1945. The core was about the size of an orange and weighed 13.5 pounds.

  17. Physicists Norris Bradbury and Boyce McDaniel stand at the top of a 100 foot tower after helping to assemble the world's first atomic bomb on July 15, 1945, one day before the Trinity test. The device was nicknamed the "Gadget."

  18. Photo of Trinity test site - Ten seconds after detonation

  19. Oppenheimer and Leslie Groves inspect the tower.

  20. Facts about the Bomb’s Test • Before dawn – July 16, 1945 – “gadget” tested • Fireball so bright – blind girl saw flash • Cloud rose eight miles into the sky • Force so strong windows shattered in buildings 125 miles away • Crater left in Earth was 1,200-foot-wide • People were told an ammunition dump exploded • The sand directly under the tower got so hot that it turned to glass

  21. More Facts about the Bomb’s Test • The explosion was equal to 20,000 tons of TNT • Half mile from the blast: everything was either vaporized or burned beyond recognition • One Mile from the blast: all buildings above ground were destroyed • Two miles: structures collapsed and rivers flowed the wrong way • Three miles away: buildings sustained severe fire and wind damage, people would have suffered second and third degree burns, if they were lucky

  22. Revelation 6:12 And I beheld when he had opened the sixth seal, and, lo, there was a great earthquake; and the sun became black as sackcloth of hair, and the moon became as blood.

  23. Harry S. Truman Vice-president Harry S. Truman taking the oath of office after the death of FDR. Not until nearly two weeks after he was sworn in was he told about the existence of the atomic bomb.

  24. Whether to Drop an Atomic Bomb Vice President Harry S. Truman became president after Roosevelt unexpectedly died in April 1945. While attending an Allied conference in Potsdam, Germany, three months later, Truman received a telegram stating that the test of the atomic bomb had been successful. By this time in the war, Germany had been utterly defeated. However, Japan had vowed to fight on, despite the Allies’ demand at Potsdam for an unconditional surrender. The Japanese felt that an unconditional surrender would jeopardize the position of their emperor, whom they considered divine (Godlike).

  25. In addition, the Japanese viewed surrender as dishonorable. They fought with fanatic resistance and believed it was more honorable to commit suicide than to surrender to enemy forces. In this vein, Japanese kamikaze pilots strapped themselves into planes loaded with explosives and crashed them into American naval vessels. They managed to destroy 53 ships and damage 158 others. The US had hoped to end the Pacific War by invading the home islands of Japan. However, in the face of Japanese fanaticism, Truman was deeply concerned that such an invasion would cost tens of thousands of American lives.

  26. In light of this concern, some of Truman’s advisors recommended that he end the war quickly by dropping a bomb without warning on a large Japanese city. The undersecretary of the navy, Ralph Bard, disagreed and told Truman that dropping the bomb without a specific warning would jeopardize “the position of the US as a great humanitarian nation.” A group of scientists from the bomb project suggested that the US drop the bomb in a remote, unpopulated location to show the bomb’s power and convince Japan to surrender.

  27. Critical Thinking Question 2 You are a close advisor to President Truman. Which of the following do you advise the president to do? Explain why.

  28. A: Without warning, drop an atomic bomb on a Japanese city as soon as possible.

  29. B:Drop the bomb on an unpopulated area to demonstrate its destructive capabilities.

  30. C:Warn the Japanese that the United States possesses atomic weapons and is willing to use them if they don’t surrender in a specified time. If they don’t surrender, then drop the bomb.

  31. D: Reject the use of atomic weapons, and continue the naval blockade and conventional bombing. If the measures do not produce a Japanese surrender, invade Japan.

  32. E: Reject the use of atomic weapons and negotiate an end to World War II, allowing the Japanese to surrender with their emperor as a part of the postwar government.

  33. Question 2: Actual Decision • August 6, 1945 – Enola Gay dropped bomb on Hiroshima; 100,000 people killed • August 9, 1945 – bomb dropped on Nagasaki; 70,000 people killed • Japan surrendered 5 days later • Truman defended his decision by saying it saved the lives of thousands of American soldiers

  34. Leaflets dropped on cities in Japan - c. August 6, 1945 TO THE JAPANESE PEOPLE: America asks that you take immediate heed of what we say on this leaflet. We are in possession of the most destructive explosive ever devised by man. A single one of our newly developed atomic bombs is actually the equivalent in explosive power to what 2000 of our giant B-29s can carry on a single mission. This awful fact is one for you to ponder and we solemnly assure you it is grimly accurate. We have just begun to use this weapon against your homeland. If you still have any doubt, make inquiry as to what happened to Hiroshima when just one atomic bomb fell on that city. Before using this bomb to destroy every resource of the military by which they are prolonging this useless war, we ask that you now petition the Emperor to end the war. Our president has outlined for you the thirteen consequences of an honorable surrender. We urge that you accept these consequences and begin the work of building a new, better and peace-loving Japan. You should take steps now to cease military resistance. Otherwise, we shall resolutely employ this bomb and all our other superior weapons to promptly and forcefully end the war. EVACUATE YOUR CITIES.

  35. ATTENTION JAPANESE PEOPLE. EVACUATE YOUR CITIES. Because your military leaders have rejected the thirteen part surrender declaration, two momentous events have occurred in the last few days. The Soviet Union, because of this rejection on the part of the military has notified your Ambassador Sato that it has declared war on your nation. Thus, all powerful countries of the world are now at war with you. Also, because of your leaders' refusal to accept the surrender declaration that would enable Japan to honorably end this useless war, we have employed our atomic bomb. A single one of our newly developed atomic bombs is actually the equivalent in explosive power to what 2000 of our giant B-29s could have carried on a single mission. Radio Tokyo has told you that with the first use of this weapon of total destruction, Hiroshima was virtually destroyed. Before we use this bomb again and again to destroy every resource of the military by which they are prolonging this useless war, petition the emperor now to end the war. Our president has outlined for you the thirteen consequences of an honorable surrender. We urge that you accept these consequences and begin the work of building a new, better, and peace-loving Japan. Act at once or we shall resolutely employ this bomb and all our other superior weapons to promptly and forcefully end the war. EVACUATE YOUR CITIES.

  36. Hiroshima, August 6, 1945

  37. Nagasaki, August 9, 1945

  38. Facts about the Bomb in Japan • Temperature at the center of blast – 100 million degrees • People at the center vaporized – remains left shadows on pavement and walls • Skin was seen peeling and hanging off of bodies • Many died of radiation poisoning – lost their hair, vomited blood, then died

  39. Whether Truman Made the Right Decision Immediately following the dropping of the two atomic bombs on Japan, the majority of Americans felt the right decision had been made. Surveys conducted by Fortune magazine in the fall of 1945 revealed that over 50% of Americans believed that the US “should have used the two bombs on cities just as we did.” Another 22.7% felt the US “should have quickly used many more before Japan had the chance to surrender.” American soldiers also supported Truman’s decision. One young soldier stated: “When the bombs were dropped and news began to circulate that the invasion would not take place after all, that we would not be obliged to run up the beaches near Tokyo assault-firing while being mortared and shelled…we cried with relief and joy. We were going to live. We were going to grow up to adulthood after all.”

  40. Many officials in the top ranks of the military and government supported Truman’s decision to drop the atomic bombs. However, others expressed doubts. Admiral William D. Leahy stated: “It is my opinion that the use of the barbarous weapon was of no material assistance in our war against Japan. The Japanese were all ready defeated and ready to surrender because of the effective sea blockade and the successful bombing with conventional weapons. My own feeling was that being the first to use the bomb, we adopted an ethical standard common to the barbarians of the Dark Ages.”

  41. Dwight D. Eisenhower, a general with enormous prestige, expressed the hope that the US would never have to use such a weapon against an enemy again because he disliked seeing the country “initiate the use of anything so horrible and destructive.” Some historians have severely criticized Truman’s decision. They argue that the Japanese were all ready defeated in August 1945, and that the atomic bombs were used primarily as a warning to the Soviet Union. Although they were allies during WWII, the US and the USSR had very different visions for the postwar world.

  42. Historians critical of Truman’s decision argue that he authorized the use of the atomic bombs mainly to scare the Soviets out of Eastern Europe and to keep them from gaining more territory in Asia. To these historians, the citizens of Hiroshima and Nagasaki were sacrificed in a high-stakes poker game between two superpowers. They also argue that the postwar nuclear arms race can be traced back to the fear and mistrust created by Truman’s decision. Other historians counter that the military pressures Truman was under at the end of WWII played a much more important role in his decision than the threat of Soviet aggression.

  43. Critical Thinking Question 3 Truman’s decision to use atomic weapons against Japan is one of the most controversial in history. In retrospect, do you think Truman made the right decision in authorizing the use of atomic weapons? Explain why.

  44. A: Truman did not make the right decision when he authorized the use of atomic weapons.

  45. B: Truman made the right decision when he authorized the use of atomic weapons.

  46. Question 3: The Debate Continues • Truman defended his decision to his death. • J. Robert Oppenheimer, the lead scientist of the Manhattan Project, said: “I am death, the destroyer of worlds.” • Albert Einstein regretted ever writing FDR. • By 1990 – approximately 100,000 nuclear weapons in existence

  47. “Fat Man” and “Little Boy”

  48. Located just under the hypocenter, only the dome-shaped framework and part of the outer wall remained. It has come to be called "the A-bomb Dome."

  49. August 6. 1945. This is one of six photographs recording the disaster of Hiroshima.

  50. The cause of keloids is not clear yet, but it is considered to be caused by a combination of powerful heat rays and radiation.