BBC Video of Liquid Explosives
The BBC has some really scary video “Detonation of Liquid Explosives.” However, as I thought about it, I grow increasingly confused by what it purports to show, and the implications.
At the end of the day, I think there are two possibilities: It’s a fair representation, or it’s not. I’m leaning slightly towards the second.
If it’s a fair representation, then why are we still drinking on planes? What’s the point of allowing us to bring in smaller amounts of stuff if a 16 ounce bottle can be bought at the airport, washed out, and used to contain whatever that is?
The second choice is that it’s misleading. First, we don’t see what’s being mixed: we see an orange powder poured into a liquid, with a jug labeled water nearby. We the expert tilting the bottle back and forth to mix it. Second, we don’t see how it’s detonated. Third, we don’t really see the placement of the bottle, or how many bottles are placed. There’s an implication that it’s one, but no statement. (In fact, there’s a lack of a statement of how much of a liquid bomb was used. The BBC website say “a liquid bomb.” We don’t see if there were squibs or other games played.
The BBC ought to tell us more about what they showed.
I would also like to know if the liquids are rather volatile and have a strong smell (along the lines of gasoline with a different smell).
It would make detection a lot easier.
But but but… If we show how to make liquid bombs then the terrorists will win since obviously only the good guys know how to make liquid explosives.
It has been reported (from the bombers’ trial) that the bomb was to be made from hydrogen peroxide, Tang fruit drink powder and a disposable camera. The Tang drink powder is mostly simple sugars, and pure H2O2 is a very strong oxidising agent but I’d expect the mixture to be fairly stable and need a high temperature trigger. The flash from the camera was supposed to provide detonation.
How much energy is in a bottle of this mixture? Half a litre of H2O2 weighs 741 grams, which gives us about 21.8 mols of O radicals to play with. Fully breaking down 1 mol of C12H22O11 needs 24 mols of O radicals (two per carbon) so we should be able to deal with about 0.91 mols of sugar, or a bit over 310 grams. Sucrose has about 17 kilo-joules of molecular energy per gram, so we should be able to release rather over 5.25 mega-joules from the bottle. By comparison, dynamite has an energy density of 7.5 mega-joules per kilogram, so the liquid bomb looks like it has the energy of 700g of dynamite. This is surely enough _energy_ to put a hole in the side of an aircraft.
So, the only remaining issues are going to be just how fast does Tang bomb chemical reaction take place and can you really trigger it with magnesium wool camera flash. Having played with medium explosives as a teenager I would not be very surprised if you can ignite this with a camera flash, especially if you have no regard for your own life in the process. I’m surprised that the reaction progresses so fast, but then again the ‘explosives expert’ was surprised too.
My guess is that the demonstration was a single half litre bottle of pure H2O2 and Tang powder, detonated with something akin to the camera flash but triggered from further away, and this was a fairly realistic demonstration of what the liquid bomb could do. Fortunately peroxide compounds are fairly easy to detect even in low levels so, to paraphrase Bruce Schneier, I refuse to be terrorised!
[Chemical constants all from Wikipedia, but errors in the math are my fault]
Thanks Nicko, for both the extra details (which I hadn’t seen) and the math.
The fast issue is indeed an interesting one–how fast does the gas expand? If it’s quick, does it rupture the bottle and drive the explosive away?
The question of mixing is also interesting–your calculations assume perfection in mixing. How far from perfection is a solution mixed in a soda bottle?
Me, I know what I’m doing this weekend!
Like all the other “let’s make ourselves safe from terrorists” systems that have been put in place, this one is designed to frighten innocent travelers and to convince them that the government is keeping us safe from terrorists. Keeping us safe from terrorists is big business these days, even if the emphasis is on the big business side and not on the safe from terrorists side.
The fast issue is indeed an interesting one–how fast does the gas expand? If it’s quick, does it rupture the bottle and drive the explosive away?
It’s a bit more complex than that. If the gas expands too fast then the heat is carried away from the unreacted mixture and the reaction slows. If it’s too slow then you get a thud not a bang, or just a small fire in the seat pocket. Ultimately for the explosion it’s all about getting the reaction to go as fast as possible, so you will want to choose a strong bottle.
The question of mixing is also interesting–your calculations assume perfection in mixing. How far from perfection is a solution mixed in a soda bottle?
Sugar is pretty soluble in water and I would guess it’s much the same in H2O2. If it fully dissolves than mixing is not an issue.
Me, I know what I’m doing this weekend!
Be very careful (a) not to blow yourself up, (b) not to get arrested and (c) to find some pure H2O2 and not the watered down stuff from the drug store, since that won’t be half as much fun!
The test was for real. ABC news in the usa has more detail on the actual test (they filmed the same test)
ITN did a similar test a week later and they also have more detail.
You can see the tang bottle in one of the ground level shots.
There were also cameras inside, its not fake.
Mickjoebill
So, I guess I should be a bit more careful in mixing my crystal lite while sitting on any flights 🙂
/me realizing now why I might have been getting some funny looks.
The original BBC test was not done by their own staff but by the MOD guys at Ft Halstead here in UK. Most of the footage I’ve seen is of the same test.
FWIW, the BBC suggested in their graphic that the camera “battery” was a modified detonator. This contradicts Nicko’s claim: “The flash from the camera was supposed to provide detonation.”
I have no idea which is correct, but I reckon we oughta have some (truth).