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| ▲ | vikramkr 3 hours ago | parent | next [-] |
| Liquid gasoline does not have anywhere near the energy of TNT, or even a battery for that matter. It contains basically zero releasable energy. It needs oxygen or another oxidizer to react with to actually release any energy. TNT and batteries' energy density calculations include the oxidizer and the oxidizer is in close proximity to the fuel (molecularly so in the case of TNT). If you 10x the "energy content" of gasoline it's still rate limited by access to oxygen. If you 10x the energy density of a battery (the type with the oxidizer contained within the battery, not a fuel cell or metal air battery) you've got 10x the energy ready to be released quickly if oxidizer and fuel mix in unfortunate ways |
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| ▲ | csours 3 hours ago | parent | next [-] | | It's an interesting discussion, because if you assume access to atmospheric oxygen, gasoline is MUCH more energy dense. TNT.....: 4 kJ/gram and 7 MJ/liter
Gasoline: 43 kJ/gram and 33 MJ/liter
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| ▲ | saltcured 2 hours ago | parent | next [-] | | The previous point is fair though. What is the energy density of gasoline in a stoichiometric mixture with its oxidizer and not already detonated? That's where TNT beats it by a long shot. The mixture with any chance of being stored would be some relatively low pressure gas. Edit: Or, a fair closed-system comparison to a battery would need to include a liquid oxygen tank or similar so you have the two components stored but can control the delivery... | | |
| ▲ | ux266478 30 minutes ago | parent | next [-] | | In the context of the conversation, it doesn't actually refute the point though, which is that explosive danger is contingent on a much broader set of relations than simple energy density. Gasoline just demonstrates the disconnect. Tacking on additional conditions to make high-density batteries dangerous is exactly what the engineering goal should be. As a stupid example, if we have a high density battery technology that never explodes unless, say, under magnetic forces only seen being produced by magnetars, that's a pretty safe battery. | |
| ▲ | SV_BubbleTime 12 minutes ago | parent | prev [-] | | Air is usually quite available though. |
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| ▲ | ranger_danger 3 hours ago | parent | prev [-] | | That's a huge assumption that won't always be the case though. A gasoline tank with a small hole in it is a lot safer than a liquid-electrolyte battery with a hole in it. | | |
| ▲ | csours 2 hours ago | parent [-] | | Yes, that's what makes it interesting. Interesting discussions about energetics are best had from a distance. | | |
| ▲ | K0balt 43 minutes ago | parent [-] | | I can remember several situations where “a little bit of gasoline” caused a lot of problems. It’s a relative term. You need a lot of air to make it really shine, but “a little bit of gas” goes a long way lol. |
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| ▲ | 2 hours ago | parent | prev | next [-] | | [deleted] | |
| ▲ | lightedman 3 hours ago | parent | prev [-] | | "Liquid gasoline does not have anywhere near the energy of TNT," Energy density of gasoline is approximately 44 to 45 megajoules per kilogram. Energy density of TNT is approximately 4.184 megajoules per kilogram. | | |
| ▲ | K0balt 39 minutes ago | parent | next [-] | | A snickers bar has nearly 5× TNT’s energy per kilogram—TNT merely has the habit of being extremely impatient about releasing it. | |
| ▲ | vitally3643 2 hours ago | parent | prev | next [-] | | [flagged] | | |
| ▲ | lightedman 2 hours ago | parent [-] | | I read it all and even what is stated is mostly wrong UNTIL THE EXACT UNIT IS SPECIFIED. And I'd know because I have to work with this IN ORBIT. I've had this conversation a dozen times in meetings with military and government. |
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| ▲ | 3 hours ago | parent | prev [-] | | [deleted] |
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| ▲ | trollbridge 3 hours ago | parent | prev | next [-] |
| One of the problems with gasoline is its explosive nature, which the fuel storage and delivery system of a car attempts to mitigate. It has a better profile for burning off than a battery though since it will spill out and burn away from the vehicle. |
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| ▲ | not_the_fda an hour ago | parent [-] | | Gasoline isn't that explosive. You can shoot up a gas tank and it will just burn. What you see on TV is movie magic. Gasoline vapor can explode, but you need the right air to fuel ratio and a spark. | | |
| ▲ | SV_BubbleTime 8 minutes ago | parent [-] | | Uh… gasoline has a super high vapor pressure. If you start out at the wrong ratio, it does what it can to make that ratio right. I’ve seen a few gasoline fires that start by burning, and then much more rapidly expressing potential. |
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| ▲ | jimt1234 10 minutes ago | parent | prev | next [-] |
| > Gasoline ... it's not a "bomb" My teen years would beg to differ, when some neighborhood friends and I decided to experiment with gas and bleach. The neighborhood residents, fire department and local police also had an opinion, too. (We all got into BIG trouble. Definitely one of the dumber things I did as a teen.) |
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| ▲ | duped 3 hours ago | parent | prev | next [-] |
| Poorly stored gasoline can spontaneously combust, though. So more like a firebomb. |
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| ▲ | ridgeguy an hour ago | parent | next [-] | | Gasoline doesn't do that. Perhaps you're thinking of the following? What it does do is slowly polymerize, becoming useless as an ICE fuel in time, typically in a year or two. This is why backup generators should run on propane, which has no degradation mechanism. | | |
| ▲ | duped 6 minutes ago | parent [-] | | No, I'm thinking of improperly stored gasoline evaporating and combusting. |
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| ▲ | not_the_fda an hour ago | parent | prev [-] | | No it can't. To combust it needs ~ 500F. If you left it out uncovered in the open and allowed the it to vaporize with a spark nearby, it might explode, but thats not spontaneous combustion. Gasoline sitting in a sealed container wont spontaneously combust. | | |
| ▲ | swiftcoder 27 minutes ago | parent [-] | | Didn't everyone have one of those old mechanic friends who liked to put the cigarette out in the can of gas to scare the tourists? | | |
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| ▲ | emptyfile 3 hours ago | parent | prev [-] |
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