Lesson 1: The Manhattan Project and Choice

Ethics: Should scientists be held responsible for how their inventions are used by the military?

Secrecy: How did the U.S. hide a project involving 130,000 people from its own public (and its allies)?

The Choice: Was Truman’s decision based purely on saving American lives, or was it a "warning" to the Soviet Union?

HIST 9–12.1: Evaluate how historical events and developments were shaped by unique circumstances of time and place.

Application: Analyzing the specific climate of fear regarding Nazi scientific progress that birthed the Manhattan Project.

HIST 9–12.14: Analyze multiple and complex causes and effects of events in the past.

Application: Investigating the chain of events from the Einstein-Szilard letter to the final decision to use the weapon.

CIV 9–12.2: Evaluate the effectiveness of various systems of government in maintaining order.

Application: Examining the power of the Executive Branch (President Truman) to make a unilateral decision that changed the course of human history.

ECO 9–12.1: Analyze how incentives influence choices that may result in policies with costs and benefits.

Application: Assessing the "cost-benefit" analysis conducted by the Interim Committee regarding an invasion of Japan versus the use of the atomic bomb.

Day 1: The Race for the Atom
Description: Students examine the discovery of nuclear fission in Germany and the subsequent letter from Albert Einstein to FDR warning that the Nazis might develop an atomic weapon.

Purpose: To establish the "fear-based" origin of the project. Students need to understand that the U.S. began this research as a defensive race against a perceived Nazi threat.

DOK Level 2: Students identify the scientific and political motivations for starting the Manhattan Project.

Day 2: Secret Cities and Industrial Scale
Description: An investigation into the massive scale of the Manhattan Project, focusing on the hidden cities of Los Alamos (NM), Oak Ridge (TN), and Hanford (WA).

Purpose: To illustrate that the bomb was not just a scientific achievement but an industrial one, involving over 130,000 workers who were largely unaware of what they were building.

DOK Level 2: Students describe the logistical challenges of maintaining absolute secrecy during a total war.

Day 3: The Trinity Test and the Scientists' Burden
Description: An analysis of the first successful detonation in the New Mexico desert on July 16, 1945. Students will read Robert Oppenheimer’s reflections and the differing reactions of the scientists present.

Purpose: To capture the "point of no return." This lesson shifts the focus from the possibility of the weapon to the reality of its world-altering power.

DOK Level 3: Students analyze the ethical concerns voiced by the scientists once the weapon's power was confirmed.

Day 4: The Interim Committee and Memos to Truman
Description: Students review primary source documents from the "Interim Committee," the group of advisors tasked with telling President Truman how and where to use the bomb.

Purpose: To examine the specific alternatives that were considered, such as a "demonstration" blast on a deserted island or a warning to the Japanese government.

DOK Level 3: Students evaluate the strategic reasons why the committee ultimately recommended using the bomb on a populated industrial target.

Day 5: The Potsdam Declaration
Description: An analysis of the ultimatum issued to Japan by the Allies in July 1945, which promised "prompt and utter destruction" if Japan did not surrender unconditionally.

Purpose: To understand the diplomatic "final warning." Students will look at why Japan's "mokusatsu" (silence/ignoring) response led the U.S. to proceed with the bombing.

DOK Level 3: Students explain the relationship between diplomatic failure and the escalation to nuclear warfare.

For ELL (English Language Learners)
Visual Concept Mapping: Use a "Project Flow" map. Place images of a lab (Discovery), a factory (Production), and a map of Japan (Application). Use arrows to show how the project moved from a "thought" to a "weapon."

Glossary of Abstract Terms: Provide a bilingual or simplified English sheet for: Fission (splitting), Ultimatum (last warning), Strategic (part of a plan), and Civilians (non-soldiers).

Primary Source Scaffolding: For the Einstein-Szilard letter, provide a "highlighted version" where the most important sentence is bolded, and the rest is summarized in 3 bullet points.

For IEP/504 (Processing & Focus)
The "Secret City" Gallery Walk: Instead of reading long texts about Oak Ridge or Los Alamos, place large photos around the room showing the fences, the workers, and the living conditions. Have students record one observation per photo.

Graphic Organizer (The Scale of Effort): Use a "By the Numbers" chart.

Workers: 130,000.

Cost: $2 Billion.

Goal: Stop the war.
This makes the abstract magnitude of the project concrete.

Simplified Decision Tree: Provide a flowchart of Truman’s options (Invasion vs. Bomb vs. Blockade). Have students draw a circle around the one they think is the "heaviest" choice.

The "Presidential Briefing"

Scenario: It is July 17, 1945 (the day after the Trinity Test). You are a senior advisor to President Truman. You must provide a 3-part briefing to help him decide the next step.

Part 1: The Scientific Success (DOK 2)

• Explain in 2 sentences what happened in the New Mexico desert (Trinity Test). Use the term Fission and describe the power of the weapon.

Part 2: The Logic of Secrecy (DOK 3)

• Why was it necessary to keep this project a secret from the American public and our Soviet allies? What was the risk if the Nazis had finished their research first?

Part 3: Evaluating the Options (DOK 4)

• President Truman has received two conflicting recommendations:

  1. Option A: Use the bomb on a military/industrial city immediately.

  2. Option B: Hold a "demonstration blast" on an uninhabited island to show Japan the power of the bomb first.

• Task: Choose one option and justify it using evidence from the Potsdam Declaration or the Interim Committee notes.