Neil deGrasse Tyson Explains Burning Gasoline

[Music] chuck yeah we had a gas pipeline hacked tell me about it oh man yeah man disrupting the the fuel pumps in the east coast of the united states and driving prices up yeah okay and that got me thinking about gasoline that's what did it okay sorry no i just got i got thinking i just want to share some thoughts i had okay about gasoline i am intrigued so it's a reminder first of all how dependent we are or at least that our transportation grid is dependent on this one source of fuel gasoline okay so so that's a that makes gasoline a strategic commodity just want to say i love it i love your government dirty talk there strategic commodity yes i'm not a government speak so so a couple of things about gasoline the reason why it is so hard to shake the gas habit yeah is uh yeah in the form of oil but it's just sitting there in the ground and chemically it contains so much energy in the form of chemical bonds did you just take it out of the ground and it used to be over here now i put it over there oh you need energy over there let me take it there right so so you it the transportability of it is a very hard habit to shake it's so transportable that you can transport it and use it at the same time [Laughter] that's exactly right right it's like let me let me put 15 gallons of gas in my car use that gas to get to my garage and i still got gas left over exactly okay so part of the evidence that it contains this energy is that gasoline is flammable okay you know extinguish all matches and cigarettes and thing when you're at the pump and now all the gas gas stations have these uh uh fire extinguisher hose you ever look up at a gas station yeah they have them right above the pump now right right above the pump and so now those tv scenes where the whole gas station is on plan that can't do it anymore you can't do it anymore because it all gets extinguished yeah and they all use like foam or halon so it's not even like you know yeah exactly exactly so just a reminder that it's flammable but there's something i think you should know about this so so flammability is not whether the thing itself will burn but will it burn in the presence of oxygen typically that's combustion wait a minute flat inflammable means flammable don't get me started on words that should be different and are not okay you know when i was 13 i looked up the definition northerly because i heard weather forecasters say northerly winds today going 15. so i looked up northerly and it said coming out of the north that was the first definition the second definition going towards the north it was like what the what about i'm in middle school and i'm supposed to make sense of this please right grown-ups can you do better than this here's my point if you have gasoline there's no oxygen in it to make it combust so if you were quick or if you came in from below you could take a match and extinguish it in the liquid gasoline a trick that i don't see it's because gasoline is not itself flammable but you know what is it's vapors right and gasoline is vaporous down to very low temperatures most things they get less smelly when you cool them down right that's why you heat food and you and the aromas and all of this gasoline at 100 degrees 50 0 10 below 20 below that is cranking out the molecules stinks of gasoline okay and what are you smelling you're smelling gasoline molecules vaporizing up and when you have a gasoline molecule floating above the liquid it is surrounded by free oxygen right in the air so when you take a match and come near a supply of gasoline it will ignite long before that match gets to the surface of the liquid it will ignite the vapors and since you're like an american guy you and you own a home you've probably tried to help the coals ignite by throwing a little gasoline of course now that's a fire that's that's this is like entry this is like like rights of passage of course except for the barbecue right tell you something you ain't had a barbecue until you had to call the fire department okay so so if you've ever done this you just might you only do it once and yet wait till your eyebrows grow back right but to take gasoline near a fire what ignites is the vapor and that's how it can make this what looks what's basically what's a conflagration a conflagration as distinct from an explosion is a moving wave of fire through whatever it is that's that's flammable and so if you have uh fumes right so here they go here they go if you ignite that those fumes will ignite and where they're going to take you to all the way back to the source yes okay that is the backdraft yes and once you do that then the whole thing goes because right above the surface of that it is more it and you'll you'll it happens quickly and fast and you basically take out the whole room so funny you bring this up right now okay oh sorry yeah cause i guess was on my mind i'm sorry no by the way so my sister and i were having this conversation yesterday because she had a fire in her how in her home and her uh housemate came downstairs and panicked when she saw the fire and my sister was trying to get the fire extinguisher going and the young woman who never took a science course in her class in her life ran to the door and opened the door to let the smoke out oh okay all right yeah to let in more oxygen is what's happening right and boom and then well if you don't know the chemistry of that it's a problem yeah and so and so for example chuck do you remember the scene in in raiders of the lost ark where uh indiana jones gets into a fight underneath that nazi airplane um at the at the at the camp at the excavation camp and they they get into a fight but and somebody shoots a gun and there's gasoline uh you know uh spilling out of the tank and it's spilling as the plane rotates so there's a there's like a path of gasoline and then there's some other fire and then it ignites right does the whole thing blow up at once no it's a moving flame on the on the vapors of the gas that finally makes its way over to the tank right okay so gasoline itself is not the thing it's got to actually catch the vapors that's all i'm saying oh by the way you know what volatile means in geochemistry i do not volatile simply means it's easy to evaporate oh okay that's a very simple easy explanation i really only know one explanation of volatile and it has to do with relationships i don't want to get into your therapy sessions here yeah yeah and pretty much all of mine have been exactly that uh there's only one factor that remains the same in all of them but we won't talk about the volatility yeah so i just want to say that in common parlance when we think of something that's volatile we think of the fact that it can ignite and by the way alcohol is among them right when you when you light alcohol you're first lighting the fumes of the alcohol and then the fumes will just stay there alcohol is not as explosive uh chemically as gasoline is but if you take a pool of alcohol and light it just watch it it's basically the the fumes above the flames last night look right the actual liquid never catches fire it's not actually on fire right it's the same with the with the sterno underneath the absolutely the sternal cup the flame is always hovering right at the opening of the start with the opening exactly yeah you got it dude that is so cool all right that's it we got it that's our that's our celebration of gasoline there you go that's the only celebration of gasoline because the take away green energy people that's the takeaway here green energy yeah time to go to electricity watch other people wait online for their one gallon of ration gas all right this is star talk explainer neil degrasse tyson keep looking up you

Channel: StarTalk

Views: 141,852

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Keywords: startalk, star talk, startalk radio, neil degrasse tyson, neil tyson, science, space, astrophysics, astronomy, podcast, space podcast, science podcast, astronomy podcast, niel degrasse tyson, physics, gasoline, chemistry, gasoline hack, pipeline, colonial pipeline

Id: 2nFH2SpoIN8

Length: 9min 37sec (577 seconds)

Published: Tue May 18 2021