physics

Nuclear testing at Bikini Atoll

Nuclear testing at Bikini Atoll is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Nuclear testing at Bikini Atoll rather than just read about it. In short: Nuclear testing at Bikini Atoll consisted of the detonation of 23 (or 24) nuclear weapons by the United States between 1946 and 1958 on Bikini Atoll in the Marshall Islands. Tests occurred at seven test sites on the reef itself, on the sea, in the air, and underwater.

Key takeaways

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Reference excerpt

Nuclear testing at Bikini Atoll consisted of the detonation of 23 (or 24) nuclear weapons by the United States between 1946 and 1958 on Bikini Atoll in the Marshall Islands. Tests occurred at seven test sites on the reef itself, on the sea, in the air, and underwater. The test weapons produced a combined yield of about 77–78.6 Mt of TNT in explosive power. After the inhabitants agreed to a temporary evacuation, to allow nuclear testing on Bikini, which they were told was of great importance to humankind, two nuclear weapons were detonated in 1946. About ten years later, additional tests with thermonuclear weapons in the late 1950s were also conducted. The first thermonuclear explosion was much more powerful than expected, and created a number of issues, but did demonstrate the dangers of such devices. The United States and its allies were engaged in a Cold War nuclear arms race with the Soviet Union to build more advanced bombs from 1947 until 1991. The first series of tests over Bikini Atoll in July 1946 was codenamed Operation Crossroads. The first bomb, named Able, was dropped from an aircraft and detonated 520 ft (160 m) above the target fleet. The second, Baker, was suspended under a barge. It produced a large Wilson cloud and contaminated all of the target ships. Chemist Glenn T. Seaborg, the longest-serving chairman of the Atomic Energy Commission, called the second test "the world's first nuclear disaster." A third test, Charlie, was cancelled due to concerns over the lingering radiation from Baker's detonation. The second series of tests in 1954 was codenamed Operation Castle. The first detonation was Castle Bravo, which tested a new design utilizing a dry-fuel thermonuclear bomb. It was detonated at dawn on March 1, 1954. Scientists miscalculated: the 15 Mt of TNT nuclear explosion far exceeded the expected yield of 4–8 Mt of TNT (6 predicted). This was about 1,000 times more powerful than either of the atomic bombs dropped on Hiroshima and Nagasaki during World War II. The scientists and military authorities were shocked by the size of the explosion, and many of the instruments that they had put in place to evaluate the effectiveness of the weapon were destroyed. Authorities had promised the Bikini Atoll's residents that they would be able to return home after the nuclear tests. A majority of the island's family heads agreed to leave the island, and most of the residents were moved to the Rongerik Atoll and later to Kili Island. Both locations proved unsuitable to sustaining life, and the United States provides residents with on-going aid. Despite the promises made by authorities, these and further nuclear tests (Redwing in 1956 and Hardtack in 1958) rendered Bikini unfit for habitation, contaminating the soil and water, making subsistence farming and fishing too dangerous. The United States has paid more than $300 million into various trust funds to compensate the islanders and their descendants. A 2016 investigation found radiation levels on Bikini Atoll as high as 639 mrem/yr (6.39 mSv/yr), well above the established safety standard for habitation. However, Stanford University scientists reported "an abundance of marine life apparently thriving in the crater of Bikini Atoll" in 2017.

Preparation The major preparation was to relocate the residents after discussion with them. At the time it was thought it would be a temporary relocation. As time showed, the nuclear weapons contaminated the area in a way that made them dangerous to live in for an extended period.

Residents relocated

In February 1946, the United States government forced the 167 Micronesian inhabitants of the atoll to temporarily relocate so that testing could begin on atomic bombs. King Juda agreed to the request, announcing that "we will go believing that everything is in the hands of God." Nine of the eleven family heads chose Rongerik as their new home. Navy Seabees helped them to disassemble their church and community house and prepare to relocate to their new home. On March 7, 1946, (now known as Bikini Day) the residents gathered their belongings and building supplies. They were transported 125 mi (201 km) eastward on Navy landing craft 1108 and LST 861 to the uninhabited Rongerik Atoll, which was one-sixth the size of Bikini Atoll. No one lived on Rongerik because it had an inadequate water and food supply, and also due to traditional beliefs that the island was haunted by the Demon Girls of Ujae. The Navy left them with a few weeks of food and water which soon proved inadequate.

Military services

The United States assembled a support fleet of 242 ships that provided quarters, experimental stations, and workshops for more than 42,000 personnel. The islands were primarily used as recreation and instrumentation sites. Seabees built bunkers, floating dry docks, 75 ft (23 m) steel towers for cameras and recording instruments, and other facilities on the island to support the servicemen. These included the "Up and Atom Officer's Club" and the "Cross Spikes Club", a bar and hang-out created by servicemen on Bikini Island between June and September 1946. The "club" was little more than a small open-air building which served alcohol to servicemen and provided outdoor entertainment, including a ping pong table. The "Cross Spikes Club" was the only entertainment that the enlisted servicemen had access to during their June to September stay at Bikini.

Ship graveyard The Navy designated Bikini Atoll lagoon as a ship graveyard, then brought in 95 ships, including carriers, battleships, cruisers, destroyers, submarines, attack transports, and landing ships. The proxy fleet would have comprised the sixth largest naval fleet in the world if the ships had been active. All carried varying amounts of fuel, and some carried live ordnance.

Weapons tests

Operation Crossroads

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Nuclear testing at Bikini Atoll

Start with the simplest possible case. Write down what Nuclear testing at Bikini Atoll claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Nuclear testing at Bikini Atoll before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Nuclear testing at Bikini Atoll ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Nuclear testing at Bikini Atoll

In research: Nuclear testing at Bikini Atoll appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Nuclear testing at Bikini Atoll in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Nuclear testing at Bikini Atoll is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1940s in the Marshall Islands, 1950s in the Marshall Islands, American nuclear test sites, so understanding it makes those chapters shorter.
In everyday life: Look for Nuclear testing at Bikini Atoll outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Nuclear testing at Bikini Atoll in 20 minutes

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Frequently asked questions

What is Nuclear testing at Bikini Atoll in simple terms?

Why does Nuclear testing at Bikini Atoll matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Nuclear testing at Bikini Atoll?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Nuclear testing at Bikini Atoll.