The Atomic Bomb

What do you know about the atomic bomb?

Why should you care about the atomic bomb?

Who Built the Atomic Bomb?

• Why did they build it?• Why was it used?• How was the decision made to use it?

Albert EinsteinFranklin D. Roosevelt

J. Robert OppenheimerHarry Truman

Albert Einstein

•Father of Quantum Physics-”E=mc2”

•Letter to Roosevelt

“This new phenomenon would also lead to the construction of bombs, and it is conceivable... that extremely powerful bombs of a new type may thus be constructed.”

Franklin D. Roosevelt

•President of the United States, 1932-1945•The Uranium Committee (1939)•Office of Scientific Research and Development (1941)•The Manhattan Project (1942)

J. Robert Oppenheimer

• Scientific director of Manhattan Project• “Father of the Atomic Bomb”• Los Alamos National Laboratory• Atomic Energy Commission• Accused of Communist Ties.

Harry Truman

• Became President upon Roosevelt’s death• Gave the order to drop the atomic bombs

on Hiroshima and Nagasaki

Little Boy

Gun-type uranium fission bombYield: 15 kilotonsDropped on Hiroshima, 6 August 1945Casualties: 140,000

Fat Man

Implosion-type plutonium fission bombYield: 21 kilotonsDropped on Nagasaki,9 August 1945Casualties: 90,000

Trinity• Alamogordo, New Mexico• July 16, 1945• First human-made nuclear explosion• Implosion-type weapon• 20 kiloton yield• News of successful test relayed to

Truman at Potsdam• Potsdam Declaration

“And now I am become Death, destroyer of worlds.”

- J. Robert Oppenheimer

Hiroshima,25 July 1945

Hiroshima,11 August 1945

Why Did Truman Drop the Bomb?

• To make an invasion of Japan unnecessary

• To intimidate the Soviet Union"Having found the bomb we have used it. We have used it against those who attacked us without warning at Pearl Harbor, against those who have starved and beaten and executed American prisoners of war, against those who have abandoned all pretense of obeying international laws of warfare. We have used it in order to shorten the agony of war, in order to save the lives of thousands and thousands of young Americans.”

-Harry Truman

Make an Invasion of Japan Unnecessary

• Okinawa (March-June, 1945)• Casualties-American: 13,000 killed, 39,000

wounded; Japanese, 131,000 killed; Civilians, 100,000 killed.

• Projected Casualties for Operation Downfall: 46,000-280,000 killed, up to a million total

The Soviet Union

• Divided Europe

• Soviet numerical superiority

CriticismsAdmiral Chester Nimitz (Commander in Chief, US Navy Pacific Fleet):

“The Japanese had, in fact, already sued for peace before the…destruction of Hiroshima… The atomic bomb played no decisive part…in the defeat of Japan.”

Admiral William Leahy: (Chairman, Joint Chiefs of Staff)“…the use of this barbarous weapon…was of no material assistance in our war against Japan. The Japanese were already defeated and ready to surrender.... in being the first to use it, we had adopted an ethical standard common to the barbarians of the Dark Ages.”

US Strategic Bombing Survey (War Department):“…certainly prior to 31 December 1945, and in all probability prior to 1 November 1945, Japan

would have surrendered, even if the atomic bombs had not been dropped, even if Russia had not entered the war, and even if no invasion had been planned or contemplated."

Dwight D. Eisenhower (Supreme Commander of the Allied Powers, President of the United States):

"...the Japanese were ready to surrender and it wasn't necessary to hit them with that awful thing."

RAFT Activity

• Role: Advisor to the President• Audience: President Harry Truman• Format: Persuasive Argument• Topic: Should the US drop the atomic bomb

on Japan?It is August 1, 1945. You have heard the arguments for and against dropping the bomb on Japan. Using the information you’ve been given, write a paragraph or two recommendation to the President for or against dropping the bomb, and explain your reasoning!

Wrap-up• Share your recommendations with the

class!• Video: “We’ll Meet Again”-Vera Lynn

Thank you for having me here today!