Attempted London Bombings

[natalie_1982]

So the bombs yesterday had been detonated but didn't go off?

I don't understand what is the difference between them being detonated or exploded?  I mean, if they were detontaed why didn't they go off?  Sorry if this is completely obvious but I don't know why.

[OBonio]

No idea how to make a bomb, but I'd say it was something to do with bad wiring. The other question that should be asked is how could all 4 bombs not go off? I don't believe in coincidence that much. Seeing as all 4 managed to go off 2 weeks ago.... I smell a rat.

[nedflanders]

read this http://news.bbc.co.uk/1/hi/uk/4705939.stm

[Grunty]

The detonator makes a little bang that sets off the explosive.  In this case, the explosives might have been made a fortnight ago but not kept properly.  Some explosives have a short shelf life in the wrong conditions.

[MargeB]

Yeah, need to keep them cold. These were wrapped in newspaper in an attempt to do that. London Underground is a very warm place.

Two attempts now in a fortnight...I think they'll introduce special measures...bag scanners, or no bags.

[Chillum]

I'd have thought it was highly likely that if one failed, all would fail. They would have all been made by the same person, so if he was incompetent, then he'd have been incompetent in each case. They would all have been stored in the same conditions, so if that had affected one it would effect all. They would all have been made from the same batch of explosives, so if it was dodgy, all the bombs would be, and the detonators would also have been from the same batch so the same goes.

[nedflanders]

"Made in Pakistan" !

[OBonio]

Yes, but I get the feeling these aren't school boys playing with their chemistry sets. If made by the same person, would they get it that wrong 4 times?

I think it's more likely they weren't meant to go off and it was just the terrorists saying 'you may be on high alert, but we can still get through'.

[Gevs1966]

The traces of explosives found look like they were from the same batch as the bombs last week and as mentioned above, this particular type of explosive has a short shelf life and would have been "out of date" and not fit for purpose.

[Loosehead]

Well a bomb has a main charge and a detonator. Now the main charge is made of an explosive that has to be very stable or it would go off very easily before you could get it in place. In order to make the main explosive go off when you want it to, you have to be able to generate enough energy in the main explosive itself, the best way to do that is with a detonator, designed for the purpose in this case the detonator was a small explosion among the main explosive but for whatever the reason, some explored above, the energy release by the detonator was not enough to set off the main, ie big bang, charge so all that happenned was a much smaller than intended explosion, still dangerous but not as bad as the main charge. Hope that helps Nat.

[Hippy]

RATHER GRIM - SQUEAMISH? DON'T READ!

The sort of bomb material used in the successful (?) bombings does not exploe with flames and hot chunks but by a rapid chemical decomposition in which complex molecules rapidly turn from solid to gas, increasing in volme greatly. The shock wave thus produced does the damage. It is similar to the device that inflates your airbag when you have a crash.

However, the amateur bomb makers produce a substance that is rather unstable. Not that it will go off by itself, but rather that it will degrade and not work after a short time. It is highly sensitive to shock and heat when first made, and it is during this phase that many bomb makers have been killed or maimed. A little later it becomes more resilient and can be used in the terrorist bombs. It can be carried around safely but set off by a percussion cap, a sort of mini explosion with the strength of a champagne cork set off by electricity. Leave the stuff, even in the fridge, for more than a few days and it is pretty useless as an explosive.