Questions: The Manhattan Project: Science, War, and Nuclear Policy

Question 1

The Manhattan Project required physicists to confront a moral question unprecedented in science: that their research would produce weapons killing hundreds of thousands of civilians. How did the scientists respond?

Model answer: Responses varied significantly. Most physicists supported using the bomb against Japan to end the war, fearing hundreds of thousands of casualties in an invasion. Some, including James Franck and Leo Szilard, signed petitions urging a demonstration on an uninhabited area before use against a city. After Hiroshima and Nagasaki, many felt profound guilt and engaged in postwar activism: Szilard, Einstein, Russell, and others founded the Bulletin of the Atomic Scientists (1945) and its famous Doomsday Clock. Oppenheimer quoted the Bhagavad Gita: 'Now I am become Death, the destroyer of worlds.' Edward Teller advocated for the hydrogen bomb and became a model of the scientist advocating for ever-more-destructive weapons.

The Manhattan Project physicists' moral responses illustrate that scientists are not morally neutral — they have political responsibilities — but that their responses to those responsibilities varied enormously.

Question 2

What was the 'Franck Report' (1945), and what did it recommend?

• A. A technical report on the bomb's expected explosive yield and radiation effects
• B. A report from Manhattan Project scientists recommending a demonstration use of the bomb before deploying it against a Japanese city
• C. The report confirming that Germany had abandoned its nuclear weapons program
• D. An assessment of Soviet nuclear capabilities prepared for the Truman administration

Answer: (B)

The Franck Report (June 1945), drafted by James Franck and signed by several Chicago Manhattan Project scientists, argued that using the bomb against a Japanese city without warning would shock world opinion, undermine the possibility of international arms control, and start an arms race. They recommended demonstrating the bomb's power on an uninhabited area or in Japan with warning, allowing Japan to surrender before a city attack. The report was ignored by the Military Policy Committee. The bombs were dropped on Hiroshima (August 6) and Nagasaki (August 9), 1945.

Question 3

The Manhattan Project is often cited as establishing the model of 'Big Science.' What specific organizational features set it apart from previous scientific research?

Model answer: The Manhattan Project differed from previous science in scale, organization, and state direction. It involved approximately 130,000 people at multiple sites (Los Alamos, Oak Ridge, Hanford, Chicago Metallurgical Laboratory). It integrated theoretical physics, industrial chemistry, engineering, and logistics — disciplines that had never collaborated at this scale. Security compartmentalization meant most workers had no idea what they were building. The state directed research goals and timelines; scientists were employees of a government program rather than independent investigators. Leslie Groves (Army general) and Oppenheimer (scientific director) jointly managed an effort that cost roughly $2 billion — orders of magnitude beyond any previous scientific project.

The Manhattan Project established that governments could organize and fund science at industrial scale for specific national objectives. This model shaped Cold War science funding and remains influential in how large-scale scientific projects are organized.

Question 4

The decision to drop atomic bombs on Hiroshima and Nagasaki was made entirely by physicists who built the bombs.

• T. True
• F. False

Answer: False

The decision was made by political and military authorities — President Truman, Secretary of War Stimson, and military advisers — not by the scientists. The scientists' role was to build the weapon; they had no formal decision authority over its use. Some scientists, like Szilard, attempted to influence the decision (the Franck Report, petition campaigns) but were largely excluded from the decision-making process. This separation of scientific production from political decision-making about weapons use is itself a significant feature of the Manhattan Project model — and of subsequent weapons programs.

Question 5

Why did the Manhattan Project succeed in producing a weapon before Nazi Germany, when Germany had a head start?

Model answer: Germany's nuclear weapons program (the 'Uranium Club') had several disadvantages: German military leadership did not prioritize it highly enough for resource allocation; key Jewish physicists (Einstein, Szilard, Fermi, Meitner, many others) had fled Germany by 1933-1938; Werner Heisenberg's program made technical errors in calculating critical mass; Allied bombing disrupted heavy water production in Norway essential to German reactor designs. The US program benefited from an enormous industrial base, protected geography, and the talent of the refugee physicists who had fled European fascism. Many of the Manhattan Project's leaders were European Jews directly fleeing Hitler.