| rdfs:comment
| - Little Boy was the codename for the type of atomic bomb dropped on Hiroshima on August 6, 1945 by the Boeing B-29 Superfortress Enola Gay, piloted by Colonel Paul W. Tibbets, Jr., commander of the 509th Composite Group of the United States Army Air Forces. It was the first atomic bomb to be used as a weapon. The Hiroshima bombing was the second artificial nuclear explosion in history, after the Trinity test, and the first uranium-based detonation. Approximately of matter in the bomb was converted into the energy of heat and radiation. It exploded with an energy of .
- The bomb that dropped on Hiroshima was code-named 'Little Boy'. The amount of energy 'Little Boy' generated when it exploded was the equivalent of a 15 kiloton TNT explosion - yet the above photograph shows that the bomb itself was relatively small despite its huge explosive capability. Half of that energy was consumed when the explosion generated an ultra high air pressure which resulted in a very strong bomb blast. One third of the rest of the energy created was consumed when the explosion generated heat, while the rest of the energy that was created was consumed in the creation of radiation.
|
| abstract
| - Little Boy was the codename for the type of atomic bomb dropped on Hiroshima on August 6, 1945 by the Boeing B-29 Superfortress Enola Gay, piloted by Colonel Paul W. Tibbets, Jr., commander of the 509th Composite Group of the United States Army Air Forces. It was the first atomic bomb to be used as a weapon. The Hiroshima bombing was the second artificial nuclear explosion in history, after the Trinity test, and the first uranium-based detonation. Approximately of matter in the bomb was converted into the energy of heat and radiation. It exploded with an energy of . Little Boy was developed by Lieutenant Commander Francis Birch's group of Captain William S. Parsons's Ordnance (O) Division at the Manhattan Project's Los Alamos Laboratory during World War II. Parsons flew on the Hiroshima mission as weaponeer. The Little Boy was a development of the unsuccessful Thin man nuclear bomb. Like Thin Man, it was a gun-type fission weapon, but derived its explosive power from the nuclear fission of uranium-235. This was accomplished by shooting a hollow cylinder of uranium over another hollow enriched uranium cylinder by means of four silk bags of cordite powder. It contained of enriched uranium, of which less than a kilogram underwent nuclear fission. Its components were fabricated at three different plants so that no one would have a copy of the complete design. After the war ended, it was not expected that the inefficient Little Boy design would ever again be required, and many plans and diagrams were destroyed, but by mid-1946 the Hanford Site reactors were suffering badly from Wigner's disease, so six Little Boy assemblies were produced at Sandia Base. The Navy Bureau of Ordnance built another 25 Little Boy assemblies in 1947 for use by the nuclear-capable Lockheed P2V Neptune aircraft carrier aircraft. All the Little Boy units were withdrawn from service by the end of January 1951.
- The bomb that dropped on Hiroshima was code-named 'Little Boy'. The amount of energy 'Little Boy' generated when it exploded was the equivalent of a 15 kiloton TNT explosion - yet the above photograph shows that the bomb itself was relatively small despite its huge explosive capability. Half of that energy was consumed when the explosion generated an ultra high air pressure which resulted in a very strong bomb blast. One third of the rest of the energy created was consumed when the explosion generated heat, while the rest of the energy that was created was consumed in the creation of radiation. Directly beneath the centre of the explosion (the hypocentre), the temperature rose to about 7,000 degrees F. Directly underneath the hypocentre and not far from this point the damage was massive. Yet buildings etc. that had areas protected by a human body were relatively unchanged as the body had taken the full impact of the heat and had absorbed it. The heat created was so great that clothes caught fire on people over one and a quarter miles from the centre of the explosion; roof tiles a third of a mile away melted. 'Little Boy' also created ultra high pressure. The wind speed on the ground directly beneath the explosion was believed to have been 980 mph and this speed generated a pressure the equivalent to 8,600 lbs per square feet. One third of a mile from the bomb blast, the wind speed was thought to be 620 mph which created a pressure of 4,600 lbs per square feet. Such a force would simply flatten most buildings - which is why the post-bomb photographs of Hiroshima show barely any buildings standing. One mile from the centre of the blast, the wind speed was still 190 mph and this speed created a pressure the equivalent of 1,180 lbs per square feet. Such a force would still be very capable of bringing down the most sturdy of buildings. The explosion of 'Little Boy' also created alpha, beta, gamma and neutron rays. Alpha and beta rays were absorbed by the air but gamma and neutron rays did reach the ground and it was these rays that affected the people of Hiroshima. Radiation poisoning killed many people in the city. Nearly all the people who survived the bomb blast but lived within a half-mile of it died within 30 days. People who entered the zone around where the bomb had been most devastating were also exposed to very high levels of radiation if they did so in the first 100 hours after the explosion. Deaths from radiation were very common for years after the explosion of 'Little Boy'. The city government of Hiroshima kept records from 1952 on but it is estimated that from August 1946 to 1952, some 60,000 people died of radiation poisoning - an average of 8,500 a year. Maybe as many as 200,000 people died as a result of 'Little Boy'.
|
![[RDF Data]](/fct/images/sw-rdf-blue.png)