Hiroshima bomb

[waiglet]

Does anyone know if the bomb exploded on impact or in the air?

Many thanks in advance.

[Loosehead]

It was an air blast not sure how High, I think approx 500ft

[KebabMeister]

It was an airburst and exploded at 580 metres.

http://www.johnstonsarchive.net/nuclear/radevents/1945JA P1.html

[betweenjobs]

Detonating it in the air made it far more devastating.

[Octavius]

"Little Boy" is the nick name given to the atomic bomb dropped on Hiroshima on August 6, 1945.

After being released, it took about a minute for Little Boy to reach the point of explosion. Little Boy exploded at approximately 8:15 a.m. (Japan Standard Time) when it reached an altitude of 2,000 ft above the building that is today called the "A-Bomb Dome."

On the ground, beneath the explosion center(hypocenter), the temperature rose to approximately 7,000 degree F. On the stairway of the entrance to a bank, which was 1/8 mile from the explosion center, a man was sitting waiting for its opening. The surface of the stone stairway was changed by the immense heat. The part where the man was sitting remained unchanged because his body absorbed the heat.
Roof (ceramic) tiles on houses within 1/3 mile radius from the explosion center melted, and gray stones which contained silicon particles became white. The clothes which people wore were burnt by the heat within 1 1/4 mile radius from the explosion center.

[waiglet]

Thanks to everyone. Great answers, very helpful.

[Larry T]

'Little Boy' was the ONLY nuclear weapon ever exploded which used enriched Uranium - ALL the other weapons have used Plutonium.  Given this, one wonders why the Bush administration is making such a fuss about Iran producing enriched-Uranium.

Before anyone 'shoots' at me, - saying that enriched-Uranium can be used in reactors to make weapon grade Plutonium, - it is very easy to tell the difference between weapon  grade Plutonium production and non-weapon grade Plutonium production in civil power reactors.