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The Bomb Question. The Manhattan Project Szilard, as always, was both a man of vision and a man of action. Well known among European physicists, Szilard.

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Presentation on theme: "The Bomb Question. The Manhattan Project Szilard, as always, was both a man of vision and a man of action. Well known among European physicists, Szilard."— Presentation transcript:

1 The Bomb Question

2 The Manhattan Project Szilard, as always, was both a man of vision and a man of action. Well known among European physicists, Szilard drafted a letter in consultation with Albert Einstein that was addressed from Einstein to President F.D. Roosevelt and which warned him of the possibility of nuclear weapons (the "Einstein Letter"). This letter was delivered to FDR on October 11, 1939, and ten days later the first meeting of the Advisory Committee on Uranium (the "Briggs Uranium Committee") was held in Washington, DC on Pres. Roosevelt's order. Einstein and Szilard

3 After several steps and secret research on June 18, 1942, Brig. Gen. Steyr ordered Col. James Marshall to organize an Army Corps of Engineers District to take over and consolidate atomic bomb development. During August Marshall created a new District organization with the intentionally misleading name "Manhattan Engineer District" (MED), now commonly called "The Manhattan Project".

4 Despite its official founding in August, the Manhattan Project really began on September 17, 1942 when Col. Leslie Richard Groves was notified at 10:30 a.m. by Gen. Brehon Somervell that his assignment overseas had been cancelled. Groves, an experienced manager who had just overseen the colossal construction of the Pentagon, seized immediate and decisive control. In just two days he resolved issues that had dragged on for months under Compton. On September 18 Groves ordered the purchase of 1250 tons of high quality Belgian Congo uranium ore stored on Staten Island, and the next day purchased 52,000 acres of land to be the future site of Oak Ridge. Groves was promoted to Brigadier General on September 23. By September 26 Groves had secured access to the highest emergency procurement priority then in existence (AAA).

5 On October 15, 1942 Groves asks Dr. J. Robert Oppenheimer to head Project Y, the new planned central laboratory for weapon physics research and design. The site for which he selected on November 16 at Los Alamos, New Mexico.

6 Additional Project Locations

7 Trinity Tests The bomb used in the first test at Trinity Site on July 16, 1945, in New Mexico, and in the Nagasaki bomb, Fat Man, were made primarily of plutonium- 239, a synthetic element.

8 The Trinity Test The first test was a great success. Harry S. Truman responded by saying: This is the greatest thing in history. J. Robert Oppenheimer had a surprising response: I have become death, the destroyer of worlds.

9 Little Boy The uranium bomb was a gun-type fission weapon. One mass of U-235, the "bullet," is fired down a more or less conventional gun barrel into another mass of U-235, rapidly creating the critical mass of U-235, resulting in an explosion. The method was so certain to work that no test was carried out before the bomb was dropped over Hiroshima, though extensive laboratory testing was undertaken to make sure the fundamental assumptions were correct. Also, the bomb dropped used all the existing extremely highly purified U-235 (and even most of the highly purified material) so there was no U-235 available for such a test anyway. The bomb's design was known to be inefficient and prone to accidental discharge. It has been estimated that only about 15% of the fissile material went critical.

10 Gun type fission

11 Little Boy Weight 8, lbs. 4,000 kg Length 9.84 ft. 3.0 m Diameter 2.3 ft. 0.7 m

12 The Enola Gay Plane commander: Paul Warfield Tibbets, Jr Tibbets was born in Quincy in western Illinois, the son of Paul Tibbets, Sr., and the former Enola Gay Haggard. He was raised in Cedar Rapids, Iowa, where his father was a confections wholesaler. The family was listed there in the 1920 U.S. Federal Population Census. The 1930 census indicates that his family had moved and was living at the time in Des Moines. Thereafter, the family moved to Miami, Florida. Tibbets attended the University of Florida in Gainesville and was an initiated member of the Epsilon Zeta Chapter of Sigma Nu fraternity in August 6, 1945: Special bombing mission (#13) with Little Boy atomic- bomb (Lll), target: Hiroshirna (Opns Order #35, Tibbets as airplane commander with modified crew)


14 Hiroshima


16 Casualties

17 Hiroshima Casualties According to most estimates, the immediate effects of the blast of the bombing of Hiroshima killed approximately 70,000 people. Estimates of total deaths by the end of 1945 from burns, radiation and related disease, the effects of which were aggravated by lack of medical resources, range from 90,000 to 140,000. Some estimates state up to 200,000 had died by 1950, due to cancer and other long-term effects. From 1950 to 1990, roughly 9% of the cancer and leukemia deaths among bomb survivors was due to radiation from the bombs. At least eleven known prisoners of war died from the bombing.

18 Nagasaki

19 Fat Man

20 Weight 10,200 lbs (4,630 kg) Length 10.6 Feet (3.25m) Diameter 5 Feet (1.52m)

21 Fat Man: An implosion bomb The bombs used in the first test at Trinity Site on July 16, 1945, in New Mexico, and in the Nagasaki bomb, Fat Man, were made primarily of plutonium-239, a synthetic element.

22 Nagasaki On the morning of August 9, 1945, the U.S. B-29 Super fortress Bockscar, flown by the crew of 393rd Squadron commander Major Charles W. Sweeney, carried the nuclear bomb code-named "Fat Man", with Kokura as the primary target and Nagasaki the secondary target. The mission plan for the second attack was nearly identical to that of the Hiroshima mission, with two B-29's flying an hour ahead as weather scouts and two additional B-29's in Sweeney's flight for instrumentation and photographic support of the mission. Sweeney took off with his weapon already armed but with the electrical safety plugs still engaged.Bockscar Observers aboard the weather planes reported both targets clear. When Sweeney's aircraft arrived at the assembly point for his flight off the coast of Japan, the third plane, Big Stink, flown by the group's Operations Officer, Lt. Col. James I. Hopkins, Jr. failed to make the rendezvous. Bockscar and the instrumentation plane circled for forty minutes without locating Hopkins. Already thirty minutes behind schedule, Sweeney decided to fly on without Hopkins. By the time they reached Kokura a half hour later, a 7/10 cloud cover had obscured the city, prohibiting the visual attack required by orders. After three runs over the city, and with fuel running low because a transfer pump on a reserve tank had failed before take-off, they headed for their secondary target, Nagasaki.

23 Nagasaki

24 Nagasaki Casualties Casualty estimates for immediate deaths range from 40,000 to 75,000. Total deaths by the end of 1945 may have reached 80,000. The radius of total destruction was about a mile (1.6 km), followed by fires across the northern portion of the city to two miles (3.2 km) south of the bomb. An unknown number of survivors from the Hiroshima bombing had made their way to Nagasaki, where they were bombed again.

25 The Bomb Project Lets go back in time to the summer of 1945 following the successful test at Los Alamos. The estimate given to Truman was that 1 million American lives would be lost in the upcoming invasion of the mainland of Japan.

26 President Truman was given five alternatives to the ending the war versus Japan. 1)Modify the surrender terms. 2)Wait for the USSR to enter the war. 3)Invade Japan. 4)Demonstrate the bomb. 5)Drop the bomb without warning.

27 The Buck Stops Here! Now you decide: If you had been President Truman, what would you have done?

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