Units

The Hydrogen Bomb: A Unit Study

The Hydrogen Bomb: A Unit Study

On November 1, 1952, the United States detonated the first hydrogen bomb. The bomb, codenamed Mike, was detonated at 7:15 AM on the island of Elugelab in the Marshall Island group, completely vaporizing the island and leaving behind a crater beneath sea level more than one mile wide and 164 feet deep. Within the first 90 seconds after the blast the fireball reached 57,000 feet high, ultimately reaching 120,000 feet. The yield of the explosion was equivalent to a staggering 10.4 megatons of TNT, containing as much force as all the bombs dropped on Germany and Japan in World War II and 450 times more powerful than the bomb dropped on Nagasaki.

Operation Ivy

Mike was part of a larger program codenamed Operation Ivy, established by President Harry S. Truman to counter efforts by the Soviet Union to become the first country to add thermonuclear weapons to their arsenal. Joint Task Force 132, assigned the responsibility for carrying out the “Mike” test, was comprised of members from all branches of service and many renowned scientists. Work began in March of 1952 to prepare the area for testing. One aircraft carrier and four destroyers as well as more than 80 aircraft were placed close to the test area to support the effort. A two-mile-long tunnel was dug connecting two islands and filled with helium balloons and sensors to monitor the progress of the fusion reaction.

Ulam-Teller Design

The Hydrogen Bomb: A Unit StudyMike was the first test of a hydrogen bomb based on the Ulam-Teller concept. Designed by Richard Garwin, this staged device used a fission bomb primary (an atomic bomb similar to the those dropped on Hiroshima and Nagasaki in Japan during WWII) to explode a fusion bomb secondary made out of hydrogen — liquid deuterium to be exact, one of two stable isotopes of hydrogen occurring in nature. Although it was known that liquid deuterium could not be used in a deployable weapon, since deuterium requires a cryogenic cooling system to be maintained as a liquid, it could be used as a proof of concept and put the U.S. at least a year ahead of the Soviet Union in developing such a device.

Mike was physically huge with the entire assembly housed in a steel case 80 inches wide and 244 inches long, with walls 10 to 12 inches thick and weighing in at 82 tons. A six-story building was required to contain the bomb and all of the equipment needed for the experiment.

What is a Hydrogen Bomb?

Why the hydrogen bomb? Critical mass can be defined as the smallest amount of fissile material in a given area required to sustain a nuclear chain reaction. If the critical mass is exceeded, one nuclear reaction causes an average of more than one nuclear reactions releasing significant energy as the radioactive atoms come apart.

Due to the compressive forces required to smash the radioactive mass together sufficiently to create a fission explosion by exceeding the critical mass, scientists encountered a theoretical maximum explosive yield barrier. In other words, as larger and larger masses are considered (more mass equates to a larger explosion), it becomes increasingly difficult to achieve the forces required to compress them efficiently to explode all of the available radioactive material. Hence, in a bomb that relies on a fusion reaction and is self-reacting once it is triggered, theoretically there is no limit to the amount of explosive force that could be released in the detonation.

Physicist Herbert York noted after the Mike explosion, “It seemed we had learned how to brush even these limits aside [the limits of the atomic bomb] and to build bombs whose power was limitless.”

Mutually Assured Destruction (MAD) Theory

The Soviet Union as well as a handful of other countries were quickly developing similar technology. All of the pieces were in place for the Cold War’s center policy — that of Mutually Assured Destruction or MAD. Since there were, and still are, enough bombs positioned in strategic locations where it was guaranteed that not all could be destroyed by an aggressor nation, the attacked nation would still maintain enough destructive force to guarantee the complete elimination of the aggressor nation’s population. The only way therefore that the MAD policy would not hold was if the aggressor nation did not weigh the consequences of the elimination of its population or if a rouge element existed that could not be tied to a so-called nation.

 

Suggestions
  • Map the island of Elugelab in the Marshall Island group.
  • Create a timeline showing the development of the hydrogen bomb.
  • Create a compare/contrast map showing the positive and negative points of the hydrogen bomb.
  • Explain the difference between fission and fusion.
  • Write a persuasive essay reflecting your opinion on some aspect of the hydrogen bomb’s history and/or technology. You’ll find several critical thinking questions below to get you started.

 

Further Investigation

Ivy Mike — First Hydrogen Bomb Test
From “Dr. Teller’s Very Large Bomb,” a PBS documentary. Includes description of how the bomb works.
(You may want to install an ad blocker before viewing.)

 

Operation Ivy
Background information, photos and videos.

“Mike” Test
Background from PBS.

Truman Orders H-Bomb Construction
Primary source from the Truman Library. (Also see page 2.)

Race for the Superbomb: Timeline
From PBS.

Operation Ivy
30-minute video from the Federal Civil Defense Administration. Excellent resource!
(You may want to install an ad blocker before viewing.)

 

Nuclear Weapons Test Map
Showing the locations of nuclear tests around the world. From PBS.

 

Activities

Interactive Timeline
Timeline creator at ReadWriteThink.

Compare and Contrast Map
Interactive application at ReadWriteThink helpful for the suggestions above.

Persuasion Map
Interactive at ReadWriteThink that helps you develop a persuasive essay.

 

Unit Studies & Lesson Plans

Fusion: The Hydrogen Bomb
Includes a portion of the PBS American Experience video “Race for the Superbomb.” The support materials include a background essay and discussion questions.

 

Printables & Notebooking Pages

World Pacific
Eduplace map for locating Elugelab.

Hydrogen Bomb Notebooking Pages
Simple pages for narrations or wrapping up.