FalcoColumbarius wrote:Actually Mr. Flibble, I am serious about this. If you ask a fireman if gasoline burns the correct answer should be no, gasoline does not burn. In fact nothing liquid or solid burns without compression. Gases burn. What makes gasoline so volatile is the rate in which the liquid vapourizes, no? Hydrogen on the other hand is already a volatile gas to start with and as Rezdiver points out, when stored under pressure it can be potentially explosive ~ and it doesn't just blow up, it blows in all directions. Nagasaki comes to mind. However, if we go with the blowing up model then if you are sitting above the fuel source.... hmm.
The thing is, hydrogen is less dense than air, yes, it is already a gas. This is why it floats in balloons. So, if you try to coat yourself with hydrogen and set yourself on fire, it does not work very well. However, if you try the same with gasoline, well, you see what happens. The reason for this is that gasoline, is, as you stated, liquid. As it changes from liquid to gas and mixes with air it becomes flammable, or even explosive. It is this same explosion that can be used to drive a car or power a fuel-air explosive.
When it comes down to energy density, hydrogen is far lower than that of gasoline, diesel or propane. This is why hydrogen needs to be compressed - just in the same way propane is for your barbeque. The advantage is that it is easy to make from water, and it turns back into water when you burn it.
Does it burn? Well, yes. Otherwise it would be useless as a fuel. Does it explode? Sure, otherwise it would not be useful to power an engine. However, when it decompresses from a cylinder, it is safer because it floats upwards, as opposed to pooling below you in a form that is rapidly turning into a flammable gas. So, when you have a hydrogen fire, most of it is a lower temperature flame, that rapidly moves upwards with the source of ignition. With gasoline, you are stuck in the middle of the fireball.
The tradeoff of course, is that you need more hydrogen to get a comparable distance that you would compared to gasoline as hydrogen is less energy dense.
So, if given the choice, if you want to self-immolate like a monk, you are going to be far better off with hydrogen, because it won't stick to you and keep you burning.
As for Nagasaki, the "hydrogen" involved was undergoing nuclear reactions, not chemical reactions. And even that was not a hydrogen bomb. It was a plutonium bomb.
http://en.wikipedia.org/wiki/Fat_Man. Any "Hydrogen" you hear about in nuclear explosions is not common road hydrogen which is H2. H3 - known as Tritium - is what is used to enrich a nuclear explosion to increase the yield. This is what we call a hydrogen bomb. I do own some tritium as a lit pendant - because it is radioactive. However, regular hydrogen is not, not will normal hydrogen increase the yield in a nuclear explosion.
But seriously, if it was as dangerous as some make us beleive I doubt they'd be using aHydrogen powered busses to shuttle people around, nor would they sell a street legal Hydrogen powered car in California.
Good Ship 
Call me BCDelica-less