Presidential Decision
How to End World War Two
To drop or not to drop

President Roosevelt began a secret project and then died in April 1945 just as the war in Europe was ending and the Allied leaders were shifting their efforts to ending the war in the Pacific.  The final decision about the use of the not so secret weapon was left to Truman.  He had to catch up on the specifics of the bomb just to be able to make a decision about what to do.

The Manhattan Project was the code- name given to the wartime, top-secret atomic weapons program. The project was named after the Manhattan Engineer District of the U.S. Army Corps of Engineers, based in New York City, where much of the early research was done. General Leslie R. Groves, a tough, no- nonsense Army Corps of Engineers officer, was put in charge.

Enrico Fermi, an Italian physicist working with a team of fellow scientists at he University of Chicago, built the first nuclear  reactor on a squash court  under the stands of the university's football stadium.
On December 2, 1942,   the world's first self-sustaining, controlled nuclear reaction was achieved:

Fusion of plutonium isotope P-239                                                 Fission of uranium isotope U-235

There were at least two methods that could be used to produce an explosion, both expensive but possible. Extensive facilities were built at Oak Ridge,Tenn., and Hanford, Wash., to produce uranium and plutonium, the fissionable material needed for the bombs. A central laboratory to design  both bombs was established at the so-called Site Y near Los Alamos, N.M.,with Dr. J. Robert Oppenheimer in charge. A small city was built in the mountains of New Mexico where several hundred professors, specialists, workers and their families moved in secrecy.
The first bomb dropped was called Trinity and from all reports was noticed by the people in New Mexico within a 100 mile radius.

• The rapid spontaneous fission rate of plutonium 239 necessitated that a different type of bomb be designed.
• A gun-type bomb would not be fast enough to work. Before the bomb could be assembled, a few stray neutrons would have been emitted, and these would start a premature chain reaction‚ leading to a great reduction in the energy released.
• Seth Neddermeyer, a scientist at Los Alamos, developed the idea of using explosive charges to compress a sphere of plutonium very rapidly to a density sufficient to make it go critical and produce a nuclear explosion.
• The Trinity bomb was called Fat Man and measured 10 feet 8 inches long and 5 feet in diameter. It contained a sphere of plutonium.
• Conventional explosives surrounding the plutoniumwere fired so that the plutonium was compressed into a supercritical mass,producing a chain reaction and an explosion.
• Fat Man was tested in the New Mexico desert, near Alamogordo, on July 16, 1945. A blinding explosion, the world's first nuclear blast, was equivalent to 18,600 tons of TNT.  (The second “Fat Man” was dropped on Nagasaki August 9, 1945.)

Little Boy

Uranium
Dropped on Hiroshima August 6, 1945

How it works

• In essence, the Little Boy design consisted of a gun that fired one mass of uranium 235 at another mass of uranium 235, thus creating a supercritical mass.
• A crucial requirement was that the pieces be brought together in a time shorter than the time between spontaneous fissions.
• Once the two pieces of uranium are brought together, the initiator introduces a burst of neutrons and the chain reaction begins, continuing until the energy released becomes so great that the bomb simply blows itself apart.

• The uranium bomb, Little Boy, exploded at 8:16 a.m. Hiroshima time
•  43 seconds after it left the B-29 Enola Gay
• almost 2,000 feet above the ground.
•  It had a yield equivalent to 20,000 tons of TNT.
• Everything within four square miles was destroyed.
• Instantly Killed: 70,000
• Instantly Injured: 70,000
• December 1945 total death toll: 140,000
• 1950 total death toll: 200,000

Fat Man - Nagasaki

• Nagasaki was the secondary target bombed after the primary target Kokura Arsena was covered with clouds and could not be bombed
• Kokura, on the northeast corner of Kyushu, was chosen as the primary target for Fat Man because it was the enemy's principal production source for automatic weapons. It was also the site of the Mitsubishi Steel and Arms Works and was one of the largest shipbuilding and naval centers in Japan.
• Nagasaki, the secondary target, was the third largest city on Kyushu. It was also one of Japan's leading shipbuilding and repair centers. It was not considered a completely "virgin" target, however, because it had been bombed many weeks before by Twentieth Air Force bombers.
• Niigata was originally considered as a third target, but it was too far away from the other two cities.
• Fat Man was dropped on Nagasaki, Japan on August 9, 1945 from a B- 29 called Bockscar, flown by Major Charles W. Sweeney .
• The Great Artiste flown by Major James I. Hopkins, Jr. was to take pictures

Impact

• The plutonium bomb, Fat Man, exploded 1,650 feet above Nagasaki at 11:01 a.m after it left the B-29 called “Bockscar”
• It had a force of 21,000 tons of TNT.
• Everything within three square miles was destroyed.
• Instantly Killed:  40,000
• Instantly Injured:  60,000
• January 1946 total death toll: 70,000
•  1950 total death toll: 140,000

These were the choices they could vote upon:
1. Use the bombs in the manner that, from a military point of view,   is most effective in bringing  about prompt surrender at  minimum  human cost to U.S.

2. Give a military demonstration in Japan to be followed by renewed opportunity for surrender before full use of the weapon is employed.

3. Give an experimental demonstration in this country, with representatives of Japan present;  followed by a new opportunity  to surrender before full use of the weapon is employed.

4. Withhold military use of the weapon, but make a public experimental demonstration of its effectiveness.

5. Maintain as secret as possible all  developments of our new  weapons and refrain from using them in this war.

How would you end the war?

1. What decision would you have  made?
2. Where there other alternatives as  well?
3. Which ones were best for the United  States and their allies?
4. Which ones were best for Japan?
5. Justify your answer with facts, details  or examples.

Image of bomb
US Invasion Plans
Development of Atomic Bomb
Details about the following topics

FOREWORD

INTRODUCTION

MANHATTAN PROJECT INVESTIGATING GROUP

PROPAGANDA

SUMMARY OF DAMAGES AND INJURIES

MAIN CONCLUSIONS

SELECTION OF THE TARGET

DESCRIPTION OF THE CITIES BEFORE THE BOMBINGS Hiroshima Nagasaki

THE ATTACKS Hiroshima Nagasaki

GENERAL COMPARISON OF HIROSHIMA AND NAGASAKI

GENERAL DESCRIPTION OF DAMAGE CAUSED BY THE ATOMIC EXPLOSIONS

TOTAL CASUALTIES

NATURE OF AN ATOMIC EXPLOSION

CHARACTERISTICS OF THE DAMAGE CAUSED BY THE ATOMIC BOMBS

CALCULATIONS OF THE PEAK PRESSURE OF THE BLAST WAVE

LONG RANGE BLAST DAMAGE

GROUND SHOCK

SHIELDING, OR SCREENING, FROM THE BLAST

FLASH BURN

CHARACTERISTICS OF INJURIES TO PERSONS

BURNS

MECHANICAL INJURIES

BLAST INJURIES

RADIATION INJURIES

SHIELDING FROM RADIATION

EFFECTS OF THE ATOMIC BOMBINGS ON THE INHABITANTS OF THE CITIES

Eye Witness Account of by Father John A. Siemes, professor of modern philosphy at Tokyo's Catholic University