Source: http://www.childrenofthemanhattanproject.org/HISTORY/little_boy.htm
Weight: 9,700 lbs
Length: 10 ft.; Diameter: 28 in.
Fuel: Highly enriched uranium; "Oralloy"
Uranium Fuel: approx. 140 lbs; target - 85 lbs and projectile - 55 lbs
Target case, barrel, uranium projectile, and other main parts ferried to Tinian Island via USS Indianapolis
Uranium target component ferried to Tinian via C-54 aircraft of the 509th Composite Group
Efficiency of weapon: poor Approx. 1.38% of the uranium fuel actually fissioned
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Info on Fat Man
Weight: 10,800 lbs
Length: 10 ft 8 in.; Diameter: 60 in.
Fuel: Highly enriched plutonium 239
Plutonium Fuel: approx. 13.6 lbs; approx. size of a softball
Plutonium core surrounded by 5,300 lbs of high explosives; plutonium core reduced to size of tennis ball
Bomb Initiator: Beryllium - Polonium
All components of Fat Man ferried to Tinian Island aboard B-29's of the 509th CG
Efficiency of weapon: 10 times that of Little Boy Approx 1 gm of plutonium (1/3 weight of penny) converted to energy
Explosive force: 21,000 tons of TNT equivalent
Another great page on the facts surrounding Trinity.
QUOTING: Soon after the explosion, Fermi went out on a lead line tank to inspect the damage. The explosion was much more powerful than they had originally expected. The explosion was equivalent to about 20,000 tons of TNT. The land under the explosion was divided into section of destructiveness. Up to half a mile radius from the hypocenter was called the vaporization point (98% fatalities, bodies were either missing or burned beyond recognition). Everything is destroyed in this area. Temperatures almost immediately rise to 3000° to 4000° C. Up to a 1 mile radius was called the total destruction zone (90% fatalities). All the buildings above ground were destroyed. Up to a 1.75 mile radius was called the severe blast damage area (65% fatalities, 30% injuries). Large structures collapsed and damage was done to bridges and roads. Rivers were even known to flow counter-current. Up to a 2.5 mile radius was known as the severe heat damage area (50% fatalities, 45% injuries). Everything in this area had some kind of burn damage. Most of the people killed in this area were suffocated because the oxygen was used up by the fires. Up to a 3 mile radius was known as severe fire and wind damage areas (15% fatalities, 50% injuries). Homes and other buildings are damaged. People were blown around and suffered 2nd and 3rd degree burns, if they survived. The power of the bombs was inhumane and questionable. The results of the two bombs used in warfare will be examined in the next section.