How is explosive force measured

However, the temperatures reached in a nuclear explosion are very much higher than in a conventional explosion, and a large proportion of the energy in a nuclear explosion is emitted in the form of light and heat, generally referred to as thermal energy. This energy is capable of causing skin burns and of starting fires at considerable distances. Nuclear explosions are also accompanied by various forms of radiation, lasting a few seconds to remaining dangerous over an extended period of time.

Approximately 85 percent of the energy of a nuclear weapon produces air blast and shock , thermal energy heat. The remaining 15 percent of the energy is released as various type of nuclear radiation. Of this, 5 percent constitutes the initial nuclear radiation, defined as that produced within a minute or so of the explosion, are mostly gamma rays and neutrons.

The final 10 percent of the total fission energy represents that of the residual or delayed nuclear radiation, which is emitted over a period of time. This is largely due to the radioactivity of the fission products present in the weapon residues, or debris, and fallout after the explosion.

The "yield" of a nuclear weapon is a measure of the amount of explosive energy it can produce. The yield is given in terms of the quantity of TNT that would generate the same amount of energy when it explodes. Thus, a 1 kiloton nuclear weapon is one which produces the same amount of energy in an explosion as does 1 kiloton 1, tons of TNT.

Similarly, a 1 megaton weapon would have the energy equivalent of 1 million tons of TNT. One megaton is equivalent to 4.

But, writes Mills, depending on the quality of TNT, that energy might range from to Joules. For the sake of measuring explosions, scientists use a constant Joules per gram to represent that range. That's all pretty arbitrary, says Mills. Though he suggests scientists abandon the imperial system of measurement altogether and adopt a standard explosion measurement like Joules instead, a solution doesn't seem likely any time soon.

So how powerful was the explosion when measured in the less-than-perfect terms available to scientists today? The Guardian 's Emma Graham-Harrison reports that scientists estimate that the first blast came in around 3 tons of TNT, and the second hit 21 tons of TNT not kilotons, as some suggested. Comparatively, the nuclear bombs that fell on Hiroshima and Nagasaki were equivalent to 13 and 21 kilotons of TNT. Helen Thompson writes about science and culture for Smithsonian.

Dense smoke rises as fire engines arrive at the blast site after the deadly explosions in Binhai New Area in Tianjin, China. Post a Comment.