1. What was the significance of dropping the atomic bomb, then and now?
The Development and Use of
the Atomic Bomb
What was the significance of dropping the atomic bomb, then and now?

2. No Bomb for the Germans or Japanese
June 1942 – German atomic program slows down because Germany felt victory in WWII was imminent.
U.S. and Britain were not aware that the Germans decided not to build a bomb.
Japan also had an atomic program but was not successful.
If Germany and Japan had created an atomic bomb, it would be used against the Allies.
In 1942, Germany decided that the construction of an atomic bomb was too large an investment and the project would severely disrupt the economy. Another reason for Germany’s decision to abandon its nuclear program was because they already expected to win the war. The United States and Britain were unaware of Germany's decision and continued to assume that the Nazis would acquire the atomic bomb, possibly before the Allies did. This led Americans to adhere to their program and beat the Germans. The U.S. needed to construct its own program in order to keep up with the competition.

3. The Manhattan Project: Los Alamos, NM Major General Lesley R. Groves
Dr. Robert Oppenheimer

4. The Manhattan Project
Secret name for the development of the Atomic Bomb
American and European physicists discovered that the fission of uranium could a powerful weapon.
At the height of construction in mid 1944, the Project employed nearly 129,000 people. No other nation in the world had the massive industrial capacity to make this possible.
The Manhattan Project was a very top secret project to counter the German nuclear program. America felt threatened by the German program and therefore, we created our own nuclear program. Albert Einstein, a German American scientist, believed that the Germans would create an atomic bomb. However, the Germans created an atomic bomb. In June 1942, President Roosevelt transferred the atomic-bomb project to the War Department's Army Corps of Engineers. Groves' major task was to build the huge industrial facilities needed to separate the small amounts of uranium and plutonium needed for a bomb. The Manhattan Project was truly a confidential program. Even Harry Truman were not even aware of the program until he took office.

5. The Manhattan Project Cont.
To disguise this ultra-secret project, the Corps created a Manhattan Engineer District, with a headquarters initially based in New York City.
Most work done at Los Alamos, New Mexico
Clearly, the Manhattan Project was initiated as a defense mechanism. With the fear of other countries, especially Germany, establishing nuclear programs, the United States needed to start a program to defend itself. If a program was not established, the United States would be in grave danger. The Manhattan Project was top-secret, Harry Truman was not aware of the program until early Most of the Manhattan Project was centered around Los Alamos, New Mexico, under the direction of American physicist J. Robert Oppenheimer, who designed and built the first atomic bombs. On July 16,1945, the first nuclear device known as the “Gadget” (Trinity) was detonated near Alamogordo, New Mexico

6. Letter to Harry Truman April 24, 1945 Dear Mr. President,
I think it is very important that I should have a talk with you as soon as possible on a highly secret matter.
I mentioned it to you shortly after you took office but have not urged it since on account of the pressure you have been under. It, however, has such a bearing on our present foreign relations and has such an important effect upon all my thinking in this field that I think you ought to know about it without much further delay.
Faithfully yours, Henry Stimson Secretary of War
In this letter from Secretary of War Harry Stimson to President Harry Truman, Stimson hints at the top-secret atomic bomb. Stimson expresses urgency in his tone. The Manhattan Project is currently coming to an end, and the bomb is near its completion. Truman, as well as most of his administration were unaware of the full details of the Manhattan Project to ensure top security.

7. “Trinity”- First Full Test July 16, 1945
The “Trinity” test was the first successful test of a nuclear weapon. The bomb tested an implosion-design plutonium bomb. This type of bomb was used in Nagasaki. The explosion was the equivalent of 20 kilotons of TNT. The test signified the beginning of the “atomic age.”
Betting pools were set up among the observers of “Trinity” on the results of the test. Some predictions ranged from zero, a dud, to 18 kilotons of TNT to destruction of the state of New Mexico to the ignition of the atmosphere and incineration of the planet.
This first nuclear explosion cast an ominous shadow over many, especially Oppenheimer. Robert Oppenheimer later said he thought of the lines from the Hindu scripture, the Bhagavad-Gita, "I am become Death, Destroyer of Worlds."
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8. Fission Bomb
The names of the two atomic bombs were “The Fat Man” and “The Little Boy.” The Little Boy bomb was a gun-type fission bomb (shown above). Gun-type bombs generate a nuclear explosion by firing one piece of fissile material into another of the same type. In this case, the material is uranium. The bomb is gun-like in that a small wedge of uranium is fired at a larger, target piece. Upon impact, the two pieces fuse together briefly, forming what is called a supercritical mass (a mass slightly greater than what is necessary to sustain a chain reaction). The rapid release of massive amounts of energy in a limited volume creates the explosion. In the Little Boy bomb, a mass of uranium about the size of a baseball produced an explosion as powerful as 20 kilotons of TNT. (Microsoft Encarta Encyclopedia.)
Picture from – “Fission Bomb” Microsoft Encarta Encyclopedia

9. Fat Man and Little Boy “Fat Man” “Little Boy”
The picture model shown above shows the type of bombs that were dropped in Japan. In Hiroshima, the Fat Man was a gun-type assembly method bomb. In Nagasaki, the Little Boy was an implosion assembly method type bomb. Japan estimates a death toll of of 240,000. Once again, the immense radiation is detrimental to health, and can create problems such as thyroid cancer. Those that survived the bomb are called hibakusha (exposed to the bomb). Today, there are over 266,000 hibakusha in Japan.
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Fat man –
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“Little Boy”

10. New Weapons in World War II
During the last stages of the war, two new weapons were introduced: the long-range rocket and the atomic bomb.
Throughout the war, most weapons were an improved version of the weapons used in World War I.
Atomic bomb = absolute destruction.
Towards the end of the war, the American government had successfully created an atomic bomb. This atomic bomb had the potential to create absolute destruction. America beat Germany in creating the bomb and had the entire world watching. The use of the bomb could sing handedly end World War II, however, the dropping of the bomb would have adverse effects on those it was used against and those who used it.

11. Battle of Okinawa Known as “Typhoon of Steel”
Largest amphibious assault in Pacific of the War.
Operation Downfall – invasion of main islands in Japan
48,000 Americans died. 150,000 Japanese civilians died.
Japanese propaganda viewed Americans as “barbarians.” This gave the Japanese the mindset of never surrendering to an American.
The Battle of Okinawa (April 1, 1945-June 21, 1945) resulted in massive causalities and was no doubt the bloodiest battle of the Pacific Ocean. “Typhoon Steel” refers to the immense amount of gun fire. About 120,000 Japanese died. More civilians were killed than in the initial atomic bomb blast at Nagasaki and Hiroshima. Operation Downfall never occurred because the atom bombs were dropped in Hiroshima and Nagasaki. The Japanese portrayed Americans as barbarians in order to gain more support. Some civilians killed their families instead of surrendering. Also, the Japanese soldiers truly fought to the last man.
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12. Uses for the Bomb Against Germany or Japan
General Groves believed it could end World War II.
$2 billion used to build the bomb. Not using it would be a waste.
'If this weapon fizzles, each of you can look forward to a lifetime of testifying before congressional investigating committees." Gen. Groves to his staff, December 24, 1944
It was believed that he atomic bomb would be used against either Germany or Japan. Groves believed that the bomb could solely end the war. He also believed that the $2 billion investment for building the bomb could be justified by using the bomb. Secretary of War Harry Stimson said, "At no time, from 1941 to 1945 did I ever hear it suggested by the President, or any other responsible member of the government, that atomic energy should not be used in the war.“ Clearly, the atomic bomb was definitely going to be used. General Groves quote states that if the atomic bomb does not work, then his staff will face a life of questioning. \ However, he was absolutely in favor of using the deadly weapon.

13. Debate over the Bomb: American Support
Americans were suffering many casualties and the Japanese were showing no signs of possible negotiation.
A cease fire was non-negotiable.
If the United States dropped the atomic bomb, surrender and peace would probably occur.
By 1945, the Japanese and Americans inflicted a huge amount of causalities, especially at the battle of Okinawa. When Franklin Delano Roosevelt was still president in 1945, the Japanese showed no sign for peace. The Japanese repeatedly denied talks for peace and peace talks were unsuccessful. The never ending war gave rise to the potential use of the atomic bomb.

14. Potsdam Declaration July 26, 1945
Key Points:
1. We-the President of the United States, the President of the National Government of the Republic of China, and the Prime Minister of Great Britain, representing the hundreds of millions of our countrymen, have conferred and agree that Japan shall be given an opportunity to end this war.
13. We call upon the government of Japan to proclaim now the unconditional surrender of all Japanese armed forces, and to provide proper and adequate assurances of their good faith in such action. The alternative for Japan is prompt and utter destruction.
The Potsdam Declaration took place on July 26, Don’t be confused with the Potsdam Agreement, because that was something very different. The Potsdam Declaration was made by Harry S. Truman, Winston Churchill, and Chiang Kai-Shek and it basically outlined surrender terms for Japan. The first point above refers to Japan’s chance to end the war. The last point gives Japan one last chance to surrender or face “prompt and utter destruction.” (atomic bomb)
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15. Potsdam Declaration Cont.
Japan would be occupied until the declaration was signed.
The Japanese army would be allowed to return home.
Once the declaration was met, allied troops would be withdrawn.
“Japan shall be permitted to maintain such industries as will sustain her economy and permit the exaction of just reparations in kind, but not those which would enable her to re-arm for war. To this end, access to, as distinguished from control of, raw materials shall be permitted. Eventual Japanese participation in world trade relations shall be permitted. “
The Japanese were given very negotiable terms but failed to sign the declaration at first. Other aspects of the Potsdam Declaration included an end to militarism and under the Cairo Declaration, Japanese sovereignty would be limited to the islands of Honshu, Hokkaido, Kyushu, Shikoku and such minor islands as the Allies determined. Clearly the terms were lenient, especially the fact that Japan would be able to participate in world trade and rebuild their industrial economy. Unfortunately, Japan did not agree to the Potsdam Declaration until after atomic bombs were dropped.
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16. Japanese View of Unconditional Surrender
Emperor Hirohito was totally against unconditional surrender.
Americans viewed Hirohito as a symbol of military aggression
Unconditional surrender  destruction of “divine” monarchy.
  One reason why unconditional surrender was unsuccessful in negotiation was because of the Emperor Hirohito’s traditional views. He, like many of his cabinet, believed that by accepting to the Allies terms, the Japanese political system and “divine” monarchy would be destroyed. Americans hated Hirohito and many wanted him to be executed or imprisoned. Undersecretary of State Joseph Grew believed that Hirohito was "the sole stabilizing force" capable of making the Japanese armed forces accept a surrender order.
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17. Emperor Hirohito
The atomic bomb convinced the Emperor to break the deadlock of Japan’s generals and accept the Potsdam Declaration
He gave three reasons, "a collapse of domestic morale” and two military concerns: “inadequate preparation to resist the invasion and the vast destructiveness of the atomic bomb and the air attacks” (Frank, 345).
The atomic bomb was given as the main reason for the surrender of Japan
The atomic bomb allowed Japans military officials to surrender and still keep their honor. “If military leaders could convince themselves that they were defeated by the power of science but not by lack of spiritual power or strategic errors, they could save face to some extent” (Frank, 347). Therefore Japanese leaders could believe that they were beat by the element of science.

18. Saving Lives by Using the Bomb
Non-combatants were dying throughout Asia at the rate of 200,000 per month.
The complete naval blockade of Japan would have resulted in hundreds of thousands of deaths due to malnutrition, dehydration, and famine.
The atomic bomb saved thousands of American soldier’s lives
Hundreds of thousands of soldiers and civilians alike were dying every month throughout the Japanese Empire. Most Japanese soldiers only knew the Samurai style of fighting which consisted of fighting to the last man. This mentality would have yielded ten times the amount of casualties than the dropping of the atom bombs. Operation Starvation was the complete blockade of Japan, which completely cut off its imports.

19. Invading Japan?
If America did invade Japan, many Americans would have died.
Secretary of State James Byrnes claimed 500,000.
Total combat deaths after four years of war – 292,000.
It was believed that if the U.S. invaded Japan, many American lives would have been lost. Secretary of State James Byrnes claimed that the atomic bomb saved about 500,000 deaths. The U.S. military planners predicted that 20,000 – 110,000 combat deaths since November 1945 thus far. However the estimates for how many Americans would have died, will never be known. We do knot know how strong the Japanese resistance would be. Some military advisors believed that the American death toll would reach 1 million.
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20. Truman’s Motivations
Many historians believe that a main reason for the use of the bomb was retaliation for the surprise and brutal attack on Pearl Harbor.
After the bomb was dropped on Hiroshima, Truman said “This is the greatest thing in history.” and “Nobody is more disturbed over the use of atomic bombs than I am but I was greatly disturbed over the unwarranted attack by the Japanese on Pearl Harbor and their murder of our prisoners of war.
Thousands of POW”S were mistreated
Even though it is impossible to know what Truman was thinking, it can be concluded that retaliation was a main cause in the dropping of the atomic bombs. The way Truman described the greatness of the weapon shows he was happy with its results. He said, “The only language they seem to understand is the one we have been using to bombard them. When you have to deal with a beast you have to treat him as a beast.” Truman was disgusted with the Pearl Harbor massacre and how American POW’s were treated throughout the war. Truman flexed the American muscle by using the bombs.

21. Truman’s True Beliefs
“We have discovered the most terrible bomb in the history of the world. It may be the fire destruction prophesied in the Euphrates Valley Era, after Noah and his fabulous Ark.”
“I have told the Sec. of War, Mr. Stimson, to use it so that military objectives and soldiers and sailors are the target and not women and children.”
“He and I are in accord. The target will be a purely military one and we will issue a warning statement asking the Japs to surrender and save lives.”
Recovered from President Harry S. Truman’s private diary. It explicitly shows that he was against the use of atomic weapons for the destruction of Japanese civilians. However, he believed he made the right decision in using the bomb against Japan because ultimately he saved American lives. He very well knew the massive power of the bomb and was grateful that the US discovered it before Hitler or Stalin. From Truman’s July 25, 1945 diary entry.

22. The Dropping of The Atomic Bomb at Hiroshima and Nagasaki
The atom bomb was no great decision. It was merely another powerful weapon in the arsenal of righteousness.
~ Harry S. Truman
We chose a dark background to represent the atom bomb to demonstrate a dark and somber mood. The background is a picture of the mushroom cloud after the atomic bomb was dropped in Nagasaki. The pictures on the left side show the actual atom bombs and the mushroom cloud after a detonation. The font we used is “1942 Report” which we believe looks like a typewriter font. The font also looks somewhat destroyed which coincides the destruction of the atomic bomb.
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23. Hiroshima During World War II
Hiroshima, Japan had reached a population of over 381,000.
Due to evacuations, the city population dropped to 255,000 at the time of the attack.
The city’s building construction consisted of several reinforced concrete buildings and lighter structures such as small wooden workshops and houses.
Hiroshima consisted of many flimsy, wooden workshops and houses. Because of this, the city was vulnerable to immense fire damage. There were a few industrial plants located near the city. The fact that the city was built with relatively weak materials, the destruction of the atomic bomb was greater than expected.

24. Tinian Island, 1945
Little Boy Fat Man
Enola Gay Crew

25. Col. Paul Tibbets & the A-Bomb

26. The Atomic Bomb at Hiroshima
The audio above was a statement made by Harry S. Truman’s announcing the atomic bombing at Hiroshima on August 6, The audio was recorded via voice recorder from the “American Presidency Project” website because the website does not offer a direct download due to copyright issues. The picture above is of stunning mushroom cloud. Truman’s speech is confidence and assures an American victory. He mentions beating the Germans and pride in the U.S. for having the first atomic weapon. He also states some of his motivations for bombing Japan.
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27. Hiroshima – August 6, 1945 70,000 killed immediately.
48,000 buildings. destroyed.
100,000s died of radiation poisoning & cancer later.

28. Hiroshima Before The Atomic Bomb
The picture above is a model of Hiroshima pre-atomic bomb. Before the bombing, Hiroshima was a city of industrial and military significance. There were even some military camps located nearby. It was one of the few cities in Japan, nearly untouched by American bombing. Hiroshima was picked as a target location because there was a large population, no POW camps, and the hills nearby would be “spectacular” when bombed.
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29. Hiroshima After The Atomic Bomb
The model above shows the great destruction at Hiroshima. The entire city was decimated within seconds. It is estimated that 70,000 – 90,000 instantly perished. However, there are also unaccounted deaths due to the massive radiation from the bomb. About 90 percent of the buildings in the city were damaged or completely destroyed.
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30. The Mushroom Cloud
8:15 AM, “The Little Boy” was dropped over the center of Hiroshima
It exploded about 2,000 ft. above the city and had a blast the equivalent to 13 kilotons of TNT.
Due to radiation, approximately 152,437 additional people have died.
During the bombing, 70,000 – 90,000 instantly died. However, over time, the deleterious effects of radiation have taken over 150,000 lives. The radiation caused massive health damage to the inhabitants as well as future generations.
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31. Hiroshima Memorials

32. Nagasaki During World War II
Nagasaki was one of the largest seaports in southern Japan.
The city was important during the war because of great industrial activity.
Most residences and industrial buildings were made of wood.
Since the city had been permitted to grow without any strict zoning laws, most buildings and residences were constructed closely to each other.
In a sense, Nagasaki was similar to Hiroshima in an industrial aspect. Nagasaki was an important city, not only for its large seaport, but for its industrial activity during wartime. Nagasaki was very active with producing ships, military equipment, and other war time goods. Also in comparison to Hiroshima, the wood construction of houses and buildings made a nuclear attack even more devastating.

33. Nagasaki – August 9, 1945 40,000 killed immediately. 60,000 injured.
100,000s died of radiation poisoning & cancer later.

34. The Bombing: Nagasaki Before After
In the before and after pictures above, clearly the immediate effects of the bombing are disastrous. On August 1, 1945, high-explosive bombs were dropped on the city. After this bombing, school children were evacuated to rural areas. Five days later, August 6, 1945, Nagasaki experienced its first large scale-bombing. A little north of Nagasaki was a camp holding British POW’s. The atomic bomb saved their lives because they were working underground in the coal mines while the atomic bombs were dropped.
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Before
After

35. Japanese Survivors

36. Formal Warning to Japan
On August 10, 1945 thousands of leaflets were dropped over the city of Nagasaki
The leaflets called for a petition to the Emperor of Japan to stop the war and agree to thirteen consequences of an honorable surrender.
Now that the first atomic bomb was dropped on Hiroshima, top U.S. leaders felt that Japan deserved a warning before the second bomb was dropped. Thousands of leaflets were dropped on every major city in Japan. They used Hiroshima as an example of the destructive power of the US’s new weapon. America urged that Japan “accept the consequences and begin the work of building a new, better and peace-loving country.” Every leaflet concluded by saying in big bold letters, EVACUATE YOUR CITIES. These leaflets were dropped soon after the atomic bomb was dropped on Hiroshima (August 6, 1945).
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Sample Leaflet

37. Japanese Leaders After the Use of the Atomic Bombs
Even after the use of the atomic bomb on Hiroshima and Nagasaki, the Japanese were still undecided on whether to surrender
There were two opposing plans for surrender
The plan with four conditions
1. A guarantee that the imperial family will continue to reign.
2. Disarmament of the armed forces by Japan herself.
3. Trial of war criminals by Japan herself.
4. Occupation of Japan to be limited to the minimum time and places
“Only on August 9, after withstanding months of blockade and bombardment, obvious preparations for invasion, two atomic bombs, and Soviet intervention, did the Big Six formulate terms for ending the war” (Frank, 344) Evidence shows that Japan was extremely unwilling to surrender at all costs. Even after the use of atomic weapons, Japan still argued about the details of how they should surrender. Therefore, without the use of Atomic weapons, the conclusion of the war could have taken years and could have yielded massive casualties on both sides. Japanese Foreign Minister wanted to surrender only under the first condition; a guarantee that the imperial family will continue to reign. At this time, there were still many factions, making terms of surrender hard to agree on.

38. The Japanese Surrender
The Japanese surrendered on September 2,
The ceremony took place on the USS Missouri accompanied by British ships in Tokyo Bay.
Japan agreed to a ceasefire and the release of POW’s.
Japan agreed to end all hostilities and acknowledge the authority of the U.S. Supreme Commander. The Japanese Prime Minister, Prince Higashi Kuni, broadcasted an appeal to his people to obey the terms of the surrender. Japan was forced to accept its defeat “squarely”.
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39. V-J Day (September 2, 1945)

40. V-J Day in Times Square, NYC

41. The Beginning of the Atomic Age