 a quick review of the of the week and I'll just talk a little bit about review what we talked about fossil fuels and so I want to go on to this idea here of all the different types of forms of fossil fuels here's a hydrocarbon just carbons with hydrogens on them and they can be in this linear form or they can be kind of branched which makes them balled up like this and we talked about how when they are this way they have a higher vapor pressure and they and and they typically melt at a at a lower they melt more easily and let's talk about alcohols which look like hydrocarbons with OHs hung off them and it can be multiple OHs hung off them and sugars look like look like hydrocarbons with OHs and one of the carbons that doesn't have an OH has a double bond to an oxygen so here's here's glucose if if it happens that ace and that hydrocarbon that's got a carbon double bonded to an oxygen and the same carbon is got an OH then that gets a different name it's called it's called a it's called an acid or carboxylic acid one way of designating the formula on this as we this part is the COOH that's this part of the formula and and if you look across here and count all the number of carbons and hydrogens you find that there are 10 carbons and 19 hydrogens off here and so that that's so that's decanoic acid if it happens that instead of a hydrogen off that instead of that OH there it's an O and then leads to another carbon then that's our last category it's called an ester which is also the same stuff that makes flowers smell sweet so how do we extract fossil fuels from the ground we've talked about how there's sort of the old-fashioned underground method there's a sort of a highly mechanized underground method in these mountaintop methods for coal mining for oil recovery it's a it's it's evolved quite a lot but but the idea is that oil gets trapped as it's sort of trying to make its way up through the subsurface gets trapped by some impermeable cap rock and if you drill into that then you can get to that and this showing an enhanced oil recovery where gases in this case CO2 is being pumped into that that that rock to try to displace some of the oil fracking is a is a is a technique that's being used in when the rock that has the hydrocarbons is shale which for the hydrocarbons neither oil just they just they don't go through the shale very easily but if you put this cocktail of liquid in there then it cracks it in that allows and puts these fissures in and allows the hydrocarbons to flow through and finally oh almost finally we how do we refine the oil that we get out of the ground just want to draw your attention to this distillation column that's that's on this great big refinery and here's a schematic of it so the crude oil comes in here gets heated up and what happens in these columns is the more volatile components like methane methane rise higher and so if you want to extract those then you would pull off those gases from the top of the column if you want to get things like octane or in that range you would pull it off lower and lower and lower until you get the really heavy things that come off the bottom and and the other thing to just note about this is that if you if you want say more octane but what you have a lot of is these longer hydrocarbons is that you can pull them off at this level and do what's called cracking which breaks it up into smaller pieces and then then that allows you to basically get more of the high-priced components out of it which is things like octane finally then we've got how do we make electricity from burning fossil fuels or anything else here's a schematic of a of a power plant and recall that there's the one circuit here which is the water that's used to basically turn the turbines and then it gets condensed back here comes in as liquid reboiled runs turbines and so forth and then there's another system which is the part that cools that that water as it's going back into the boiler and that's the that's a condenser system often this is a lake or an ocean and so two two two water systems but I also just wanted to draw your attention to what makes the the water in the boil boil in the first place so it could be burning coal or gas or oil you could have nuclear reactions going on that that release heat you could have a solar energy array like this in this case this is in civil Spain these are individual mirrors that are all pointing the Sun's rays at this at this central location in this case there's one more step because what happens is that all this energy goes in here and it melts and probably some salts and then the salts get the molten salts end heating up the water in the boiler and that is it