Hiroshima vs Nagasaki Atomic Bomb: Difference and Comparison

The Hiroshima atomic bomb, “Little Boy,” used uranium-235 and was dropped on August 6, 1945. The Nagasaki bomb, “Fat Man,” used plutonium-239 and was detonated on August 9, 1945, marking the devastating culmination of World War II’s Manhattan Project.

Key Takeaways

1. The atomic bomb dropped on Hiroshima was a uranium-based bomb named “Little Boy,” while the one on Nagasaki was a plutonium-based bomb called “Fat Man.”
2. The Hiroshima bomb resulted in approximately 135,000 casualties, while the Nagasaki bomb caused around 64,000 deaths.
3. The bombings of Hiroshima and Nagasaki led to Japan’s surrender in World War II. They contributed to the development of international laws and treaties to prevent the use of nuclear weapons.

Hiroshima Atomic Bomb vs Nagasaki Atomic Bomb

Hiroshima Atomic Bomb nicknamed “Little Boy,” was a gun-type bomb that used uranium-235 as its fissile material, was 13 feet long, and weighed 4.5 tons. Nagasaki Atomic Bomb, nicknamed “Fat Man,” was an implosion-type bomb that used plutonium-239 as its fissile material at 10 feet long.

The bomb in Hiroshima detonated in the city center, which was densely populated with wooden housing developments and commercial establishments.

Because of these reasons, the mortality and damage in Hiroshima were exceptionally great. Hiroshima’s firestorm damaged 13 square kilometers (five square miles) of the entire city.

Almost 63 percent of Hiroshima’s structures were utterly destroyed, and more were heavily damaged.

In Nagasaki, 20,000 people perished that day, out of a total population of 174,000, with another 17,000 dying over the next four months.

And the warhead that destroyed the city was named ‘Fat Man,’ and it was a plutonium-based atomic bomb with a much more complex structure compared to the former.

Comparison Table

Feature	Hiroshima	Nagasaki
Date of bombing	August 6, 1945	August 9, 1945
Type of bomb	Uranium-gun type (“Little Boy”)	Plutonium implosion type (“Fat Man”)
Yield	Approximately 15 kilotons of TNT	Approximately 21 kilotons of TNT
Detonation altitude	Approximately 600 meters (1,968 feet)	Approximately 500 meters (1,640 feet)
Estimated immediate deaths	70,000 – 130,000	39,000 – 86,000
Total estimated deaths (including radiation-related deaths)	90,000 – 240,000	60,000 – 88,000
City size and topography	Flat river delta, population around 350,000	Mountainous terrain, population around 250,000
Building materials	Mainly wooden structures	More varied, including some fire-resistant concrete structures
Impact of blast and fire	Widespread destruction over a large area, intense firestorm	Concentrated damage in the valley, less extensive firestorm due to terrain
Impact of radiation	Significant, with long-term health effects on survivors	Similar to Hiroshima, but affected area smaller due to terrain

What is Hiroshima Atomic Bomb?

Background and Development

The Hiroshima atomic bomb, codenamed “Little Boy,” was developed as part of the Manhattan Project during World War II. The project aimed to create a powerful nuclear weapon to ensure the Allies’ strategic advantage.

Technical Details

“Little Boy” utilized uranium-235 as its fissile material. The bomb relied on a gun-type design, where two sub-critical masses of uranium-235 were brought together to form a critical mass, initiating a self-sustained nuclear chain reaction.

Deployment and Impact

On August 6, 1945, the United States dropped the Hiroshima bomb from the Enola Gay, a B-29 bomber. The explosion occurred at an altitude of approximately 600 meters above the city, resulting in a devastating blast, intense heat, and lethal radiation. The immediate and long-term effects caused unprecedented destruction, with estimates of tens of thousands killed instantly and many more succumbing to injuries and radiation-related illnesses in the following years.

Historical Significance

The bombing of Hiroshima marked the first wartime use of a nuclear weapon and had profound implications on global geopolitics, leading to Japan’s surrender and the end of World War II. The event also initiated discussions and debates about the ethical and moral considerations of nuclear warfare.

What is Nagasaki Atomic Bomb?

The Nagasaki atomic bomb, codenamed “Fat Man,” was part of the United States’ Manhattan Project during World War II. Following the success of the Hiroshima bombing, the decision to deploy another nuclear weapon was made as a strategic move to expedite Japan’s surrender.

Design and Composition

“Fat Man” was an implosion-type nuclear weapon, utilizing a spherical design. Its core consisted of plutonium-239, a fissile material, surrounded by a tamper to increase compression during detonation. The bomb also included a beryllium initiator to initiate the chain reaction.

Detonation and Impact

On August 9, 1945, the B-29 bomber “Bockscar” dropped the Nagasaki bomb over the city. The explosion, with an estimated yield of 21 kilotons, resulted in widespread destruction, causing immediate deaths, injuries, and long-term health issues due to radiation exposure. The devastating impact played a significant role in Japan’s decision to surrender, leading to the end of World War II.

Main Differences Between Hiroshima Atomic Bomb and Nagasaki Atomic Bomb

• Design and Composition:
  • Hiroshima: “Little Boy” used uranium-235, employing a gun-type design.
  • Nagasaki: “Fat Man” utilized plutonium-239 and featured an implosion-type design.
• Bomb Yield:
  • Hiroshima: “Little Boy” had an estimated yield of around 15 kilotons.
  • Nagasaki: “Fat Man” had a higher estimated yield of about 21 kilotons.
• Impact and Targets:
  • Hiroshima: Targeted on August 6, 1945, resulting in significant casualties and destruction.
  • Nagasaki: Targeted on August 9, 1945, with widespread destruction and a crucial role in Japan’s surrender.
• Role in Ending WWII:
  • Hiroshima: Marked the first use of a nuclear weapon, contributing to Japan’s surrender.
  • Nagasaki: Reinforced the message of devastating power, hastening Japan’s decision to end World War II.
• Fissile Material:
  • Hiroshima: Used uranium-235 as the fissile material.
  • Nagasaki: Used plutonium-239 as the fissile material.
• Bomb Delivery:
  • Hiroshima: Dropped by the Enola Gay on August 6, 1945.
  • Nagasaki: Dropped by the B-29 bomber “Bockscar” on August 9, 1945.

References

1. https://www.ctbto.org/specials/testing-times/6-and-9-august-1945hiroshima-nagasaki
2. https://www.britannica.com/event/World-War-II/Hiroshima-and-Nagasaki