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This article talks about what the health risks were after the atomic bomb was dropped.

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Genetic Effects of the Atomic Bombs in Hiroshima and Nagasaki

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Various studies that were conducted following the bombings of Hiroshima and Nagasaki showed no statistically significant increase in cancer risk or other pregnancy outcomes among children of survivors. However, evidence shown by later studies proves that there were alarming genetic and health effects on both the survivors and their children.

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After 6 years of war, the first atomic bombs were dropped onto the Japanese cities Hiroshima and Nagasaki. Over
200,000 soldiers and civilians were killed. 60-80 thousand were killed instantly, and about 140,000 people died of nuclear radiation by the end of that year.

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Gives info on how the bomb was created. The immense destructive power of atomic weapons derives from a sudden release of energy produced by splitting the nuclei of the fissile elements making up the bombs' core. The U.S. developed two types of atomic bombs during the Second World War. The first, Little Boy, was a gun-type weapon with a uranium core. Little Boy was dropped on Hiroshima. The second weapon, dropped on Nagasaki, was called Fat Man and was an implosion-type device with a plutonium core.

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The immense destructive power of atomic weapons derives from a sudden release of energy produced by splitting the nuclei of the fissile elements making up the bombs' core. The U.S. developed two types of atomic bombs during the Second World War. The first, Little Boy, was a gun-type weapon with a uranium core. Little Boy was dropped on Hiroshima. The second weapon, dropped on Nagasaki, was called Fat Man and was an implosion-type device with a plutonium core.

Fission

The isotopes uranium-235 and plutonium-239 were selected by the atomic scientists because they readily undergo fission. Fission occurs when a neutron strikes the nucleus of either isotope, splitting the nucleus into fragments and releasing a tremendous amount of energy. The fission process becomes self-sustaining as neutrons produced by the splitting of atom strike nearby nuclei and produce more fission. This is known as a chain reaction and is what causes an atomic explosion.

When a uranium-235 atom absorbs a neutron and fissions into two new atoms, it releases three new neutrons and some binding energy. Two neutrons do not continue the reaction because they are lost or absorbed by a uranium-238 atom. However, one neutron does collide with an atom of uranium-235, which then fissions and releases two neutrons and some binding energy. Both of those neutrons collide with uranium-235 atoms, each of which fission and release between one and three neutrons, and so on. This causes a nuclear chain reaction. For more on this topic, see Nuclear Fission.

Criticality

In order to detonate an atomic weapon, you need a critical mass of fissionable material. This means you need enough U-235 or Pu-239 to ensure that neutrons released by fission will strike another nucleus, thus producing a chain reaction. The more fissionable material you have, the greater the odds that such an event will occur. Critical mass is defined as the amount of material at which a neutron produced by a fission process will, on average, create another fission event.

The Difference Between the Bombs

Little Boy and Fat Man utilized different elements and completely separate methods of construction in order to function as nuclear weapons. Little Boy detonated due to a fission chain reaction involving the isotope U-235 of uranium, while Fat Man used plutonium's Pu-239 form.

Little Boy

Little Boy was powered by the uranium isotope U-235 in a process that didn't come easily to the many Manhattan Project scientists working on the uranium extraction and enrichment process. Most uranium found naturally in the world exists as uranium-238, leaving only 0.7% of naturally existing uranium as the U-235 isotope. When a neutron bombards U-238, the isotope often captures the neutron to become U-239, failing to fission, and thus failing to instigate a chain reaction that would detonate a bomb. The first challenge of the project was thus to determine the most efficient way to separate and purify uranium-235 from the overly-abundant uranium-238 - standard methods of separation could not be used due to the strong chemical similarity between the two isotopes. In order to avoid wasting time on one new method that could later prove insufficient to produce enough U-235 to allow the atomic bomb to reach critical mass, General Leslie Groves consulted with lead scientists of the project and agreed to investigate simultaneously four separate methods of separating and purifying the uranium-235: gaseous diffusion, centrifuge, electromagnetic separation and liquid thermal diffusion.

Once enough U-235 was obtained to power the bomb, Little Boy was constructed using a gun-type design that fired one amount of U-235 at another to combine the two masses. This combination created a critical mass that set off a fission chain reaction to eventually detonate the bomb. The two masses of U-235 had to combine with one another quickly enough to avoid the spontaneous fission of the atoms, which would cause the bomb to fizzle, and thus fail to explode.

Fat Man

Powered by plutonium, Fat Man could not use the same gun-type design that allowed Little Boy to explode effectively - the form of plutonium collected from the nuclear reactors at Hanford, WA for the bomb would not allow for this strategy. The Hanford plutonium emerged from the reactors less pure than the initial plutonium extracted from Ernest O. Lawrence's Berkeley Lab, instead containing traces of isotope plutonium-240, as opposed to the desired plutonium-239. Plutonium-240's higher fission rate would cause the atoms to undergo spontaneous fission before the gun-type design could bring two masses of plutonium together, which would lower the energy involved in the actual detonation of the bomb.

Thus, a new design was required. Physicist Seth Neddermeyer at Los Alamos constructed a design for the plutonium bomb that used conventional explosives around a central plutonium mass to quickly squeeze and consolidate the plutonium, increasing the pressure and density of the substance. An increased density allowed the plutonium to reach its critical mass, firing neutrons and allowing the fission chain reaction to proceed. To detonate the bomb, the explosives were ignited, releasing a shock wave that compressed the inner plutonium and led to its explosion.

Atom: building blocks of matter; made up of a small, dense nucleus surrounded by a cloud of electrons (negatively-charged particles)

Nucleus: makes up the center of the atom; consists of a number of positively-charged protons and a neutral (no charge) neutrons. An atom is classified by the number of protons and neutrons in its nucleus. The number of protons determines which chemical element the atom is (e.g. uranium), and the number of neutrons determines which isotope of that element the atom is (e.g. uranium-235).

Isotope: Isotopes of an element possess the same number of protons in their nuclei but have different numbers of neutrons.

Fission: the process by which an atom's nucleus is split into smaller particles; results in the release of neutrons and lots of energy.

E=mc²: Equation made famous by Albert Einstein. Explains how a tiny amount of matter contains a tremendous amount of energy.

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The immense destructive power of atomic weapons derives from a sudden release of energy produced by splitting the nuclei of the fissile elements making up the bombs' core. The U.S. developed two types of atomic bombs during the Second World War. The first, Little Boy, was a gun-type weapon with a uranium core.

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This article gives a brief summary of how the momb is made and how people found out how to make it.

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Atomic bomb | History, Properties, Proliferation, & Facts

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atomic bomb, also called atom bomb, weapon with great explosive power that results from the sudden release of energy upon the splitting, or fission, of the nuclei of a heavy element such as plutonium or uranium. When a neutron strikes the nucleus of an atom of the isotopes uranium-235 or pl…

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This Gives more info on the Impact of the bomb.
In this article the author taught me that the atomic bomb could break the barrier through discovery in breaking the atoms of uranium into different parts causing a chain reaction int a explosion.

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In 1939, the U.S. discovered that the Nazis were developing a weapon of unprecedented destructive power and began a top-secret project led by Robert Oppenheimer to beat them to it: The Manhatten Project.

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The Scientist Who Helped Discover Nuclear Fission

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The Scientist Who Helped Discover Nuclear Fission

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Lise Meitner discovered that nuclear fission could create a huge amount of energy. Nuclear fission is splitting an atom, which is really, really small. This led to the idea of the atomic bomb, but she thought that the discovery should be used for peace instead of war. Nuclear fission was discovered when hitting uraniaum with atoms.

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The Manhattan Project and the atomic bomb

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The Manhattan Project and the atomic bomb

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This can give simple background info on the topic.
The author taught me in this article about the Manhattan project. Is also taught me about the impact more on the people.

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The United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki in August 1945, killing 210,000 people-children, women, and men.

President Truman authorized the use of the atom bombs in an effort to bring about Japan's surrender in the Second World War. In the days following the bombings Japan surrendered.

The Manhattan Project was the US government program during World War II that developed and built these first atomic bombs.

Detonation of these first nuclear bombs signaled arrival of a frightening new Atomic Age.

The Manhattan Project

The Manhattan Project was the codename for the secret US government research and engineering project during the Second World War that developed the world's first nuclear weapons. President Franklin Roosevelt created a committee to look into the possibility of developing a nuclear weapon after he received a letter from Nobel Prize laureate Albert Einstein in October 1939. In his letter, Einstein warned the president that Nazi Germany was likely already at work on developing a nuclear weapon. By August 1942, the Manhattan Project was underway.

By 1944, six thousand scientists and engineers from leading universities and industrial research labs were at work on the development of the world's first-ever nuclear weapon. Robert Oppenheimer, a physicist, headed the Los Alamos National Laboratory, the Manhattan Project's principal research and development facility. For security reasons, the facility was located in the desert near Los Alamos, New Mexico.

Major General Leslie Groves oversaw the Manhattan Project for the US government. Private corporations, foremost among them DuPont, helped prepare weapons-grade uranium and other components needed to make the bombs. Nuclear materials were processed in reactors located in Oak Ridge, Tennessee and Hanford, Washington. At its peak, the Manhattan Project employed 130,000 Americans at thirty-seven facilities across the country.

On July 16, 1945 the first nuclear bomb was detonated in the early morning darkness at a military test-facility at Alamogordo, New Mexico. The intense brightness of the explosion's flash was followed by the rise of a large mushroom cloud from the desert floor. House windows more than fifty miles away shattered.

Hiroshima and Nagasaki

In May 1945, the Allies defeated Germany, two months before the atomic bomb was complete. War with Japan continued, however, and In August 1945 it seemed that an invasion of Japan itself might be necessary to force the Japanese to surrender. Military advisers to President Harry S. Truman warned that such a ground war would result in the deaths of tens or hundreds of thousands of young men in the US Armed Forces, as well as the deaths of many Japanese military personnel and civilians. After receiving no reply to his threat that "prompt and utter destruction" would follow if the Japanese did not surrender unconditionally, Truman authorized the use of the bomb on Japan.

On August 6, 1945 an American B-29 bomber named the " Enola Gay" dropped the first atomic bomb on the city of Hiroshima. The device exploded over the city with a force of 12,500 tons of TNT. "[The city] had been there just a few minutes before . . . but it was absolutely gone," said one witness. About 140,000 people were killed instantly or died due to injury or radiation poisoning within months of the blast at Hiroshima.

Truman called for surrender the day after the bombing at Hiroshima once more, but once more the Japanese government refused. On August 9, about 80,000 people died after the United States dropped a second bomb on the Japanese city of Nagasaki. A total of 210,000 civilians died in the two atomic blasts. (In comparison, the United States had killed 120,000 Japanese civilians with conventional bombs during air raids on Tokyo in March 1945.)

Six days later, after the Soviet Union declared war on Japan, the Japanese government signed an unconditional surrender. World War II was over.

The development of the atomic bomb had repercussions that would continue to resonate throughout the twentieth century, particularly in the Cold War. Spies within the research and development facility at Los Alamos-most notably the scientist Klaus Fuchs -gave the Soviet Union information about the nuclear program that helped the Soviets develop their own atomic weapon by 1949.

Was the bombing of Hiroshima and Nagasaki necessary?

Truman's decision was framed by his belief that the bombing of Hiroshima and Nagasaki would shorten the war and thereby save the lives of tens or hundreds of thousands of American soldiers as well as untold numbers of Japanese soldiers and citizens.

However, in the years following the war-and to this day-the United States' use of nuclear bombs against the civilian populations of Hiroshima and Nagasaki has had both proponents and detractors. Many questions remain about the necessity of using the bomb and its moral implications: Would the United States have acted so quickly to use nuclear weapons against Europeans? Was racism against the Japanese an element in the decision? Might the United States have exploded a nuclear bomb on an uninhabited island to demonstrate the bomb's terrible power instead of destroying two cities? Might the United States have been able to gain Japan's unconditional surrender by other means?

But there was no question that the development and use of the atomic bomb changed the nature of world warfare forever. Though the bombings of Japan remain the only wartime use of nuclear weapons, since 1945 the threat of nuclear war has loomed over international conflicts, promising a level of "prompt and utter destruction" never before seen in the world.

What do you think?

What might have happened if Nazi Germany had developed a nuclear weapon before the United States?

In what ways did scientists, engineers, corporate leaders, American workers, and the military come together in shaping the successes of the Manhattan Project?

Was the decision to drop the atom bombs on civilians morally justifiable?

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The atomic bomb & The Manhattan Project (article) | Khan Academy

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The United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki in August 1945, killing 210,000 people-children, women, and men. President Truman authorized the use of the atom bombs in an effort to bring about Japan's surrender in the Second World War. In the days following the bombings Japan surrendered.