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Author Topic: What makes the bang?  (Read 3149 times)

Offline DoctorBeaver

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What makes the bang?
« on: 17/10/2007 13:42:22 »
When a bomb is detonated (or any explosive for that matter) it goes <<BANG>> or <<<<KABOOM>>> etc. What causes that?

(I think I know the answer but I thought it would make a good topic for my landmark 400th thread-start)


 

another_someone

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What makes the bang?
« Reply #1 on: 17/10/2007 15:48:05 »
The sound of the explosion is caused by the supersonic wavefront (no different in broad terms to the crack of a whip, or the sonic boom of a supersonic aircraft) - but then, you knew that already :)
 

Offline DoctorBeaver

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What makes the bang?
« Reply #2 on: 17/10/2007 22:06:37 »
Yeah, I did - but I wanted to start my 400th topic  ;)
 

Offline kdlynn

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What makes the bang?
« Reply #3 on: 17/10/2007 23:10:02 »
and it's a lovely topic
 

Offline thebrain13

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What makes the bang?
« Reply #4 on: 18/10/2007 01:10:10 »
well what makes the bomb destroy things, what comes out of the detonation?
 

another_someone

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What makes the bang?
« Reply #5 on: 18/10/2007 04:38:12 »
well what makes the bomb destroy things, what comes out of the detonation?

It depends on the type of bomb.  For some types of bombs, heat and/or shrapnel are critical to their action, but for most bombs, it is merely the blast.

The blast itself can act in different ways, and different types of bombs are used for destroying buildings than for killing people or for damaging protected (armoured) buildings, earthworks, or vehicles.

In the simplest scenario, a fairly slow blast (which might be used to cause damage to lightly protected buildings over a wide area) would just blow things over.  For more protected installations, the shock wave would be designed to penetrate the installation, and break up the fabric of the building (in many cases, for these kinds of bombs, the shock wave can also damage human tissue).  In other cases, the heat of the bomb is used to burn up the target (these are generally what are regarded as thermobaric bombs, although some armour piercing rounds also use heat, but in a shaped charge).
 

Offline syhprum

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What makes the bang?
« Reply #6 on: 18/10/2007 14:43:38 »
During the war when bombs were falling in the London docklands area where the buildings were mostly of brick outer walls with a timber interior we were told that these buildings were strong in compression but their destruction occurred when the low pressure after the explosion caused the walls to collapse outwards
 

Offline daveshorts

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What makes the bang?
« Reply #7 on: 20/10/2007 10:54:27 »
What makes the bang depends on the type of explosive. There are two main types of explosive, high and low. Low explosives like gunpowder or cordite just burn very quickly producing lots of gas, so if they burn normally they just go whoosh a bit like a firework rocket, but if you confine them the pressure will build up until the container breaks when a lot of gas at high pressure is released producing a vibration in the air - a bang.

High explosives (such as TNT or dynamite) on the other hand burn supersonically. There is a shock wave that passes through the material which causes it to react producing more gas and making the shockwave stronger and stronger so they are much more destructive.

Low explosives are used for propellants in guns as you want a lot of gas to push the bullet forward but not to blow the barrel apart. High explosives are used in shells to blow things apart.
 

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What makes the bang?
« Reply #7 on: 20/10/2007 10:54:27 »

 

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