Methane - Periodic Table of Videos

so what I thought we'd do is investigate today an explosive mixture of methane and air and to do that we're going to use this very crude device it's just simply can now me and Neil have doctored it slightly by drilling a couple of holes okay one in the bottom and one in the top now what I'm going to do is I'm going to fill the can from my gas tap so I'm going to fill it up with gas so you can hear it fill in methane is actually found in our gas taps so here in our lab we've got a gas tap here and methane comes out of it along with some other stuff as well to actually give it the smell because normally me phone doesn't really smell of anything so this is methane carbon with four hydrogen's around it ch4 methane is the simplest compound of carbon and hydrogen and it is enormous ly widespread molecule in the world so what we're going to do is actually use this to bubble methane gas into a soapy water solution okay so that's all is just a tub of soapy water and it goes top goes on it is the basis of so called natural gas the gas that's found and deep in the earth and which you can drill down and recover it's used for heating and energy all over the world so let's show you the combustion of methane so simple combustion we're going to use a Bunsen burner I just need to light it so you can see the me thing's burning quite nicely in the atmospheric air and you're getting this rather nice incandescent flame it's also formed when plant material decomposes so if you have a pond little lake and plants material falls in and decomposes on the bottom if you stick a stick in bubbles of gas come up so all that's happening and obviously I've got the benefit be able to smell it as well as here it is that the methane gas bubbles are forming so they're soap bubbles but instead of it being air trapped inside each bubble every single bubble there has faith inside it if you collect the this gas you can actually light it with a match and it burns and I've done that when I was younger and to prove its me Fame and not just air that we're putting into it I don't have match on a stick like Pete does so that I don't burn myself I'm going to coat myself in some soapy water and then scoop up a handful of this methane is also formed when plant material decomposes inside the digestive system of an animal it's particularly dramatic and cows but it happens inside you or me that this material reacts is digested by bacteria in your digestive system part of the carpet and the food that you're eating is converted to methane and you can belch it out or expel it as wind from the other end okay now then methane gas and alkanes in general are very energetic like you can see with a flame and in fact it's similar compounds those with a bigger perhaps a higher molecular weight which are used to drive things like cars buses and planes and they basically use combustion or an explosive combustion inside the combustion engine of a car so you mix oxygen with the fuel in this case we're going to use methane in the appropriate amount such that they mix to be stoichiometric Li correct such that they explode into life and they react instantaneously and cause a big pop methane when it goes into the atmosphere behaves like carbon dioxide because it can absorb radiation infrared radiation and cause global warming and it causes the absorbs the radiation via the vibrations of the carbon hydrogen bonds and the vibrations when they stretch and also when they vibrate so called scissors vibrations now what I'm going to do is I'm going to fill the can from my gas tank so I'm going to fill it up with gas methane in fact absorbs radiation much more strongly than carbon dioxide in the atmosphere but its life time the molecule life in the atmosphere is shorter because it eventually reacts with oxygen and turns to carbon dioxide but the methane that emitted by intensive farming of cattle can be quite a contribution to global warming okay then when it's completed I'm going to set fire to the top so now I have a reservoir of gas inside my can which is burning in the atmosphere okay now then as we're using up the methane inside something really cold happening atmospheric air including oxygen is being sucked in through the hole in the bottom of the cap so as the methane is being used more air is going in so if we think about the can the amount of methane is going down and the amount of air is going up eventually they'll reach an explosive regime and something exciting might happen in the camp so we're going to walk away from him a little bit and wait so what we're looking for now is the flame on the top it's getting smaller and smaller and smaller as the burning methane gets less and less and less and then hopefully that flame will pop back inside the vessel and pop let's see it could take a while because these cans they do take a while to burn out so when the flame disappears cover your ears it's not going to be that bad so inside the can we developed an explosive regime or explosive concentration of methane and air and it instantaneously reacted and blew the top off as it made lots and lots of hot co2 and hot water vapor

Channel: Periodic Videos

Views: 254,519

Rating: 4.9436779 out of 5

Keywords: methane

Id: yXB3ULFKl0o

Length: 6min 54sec (414 seconds)

Published: Thu Feb 11 2010

Reddit Comments

[u/IsaacNewton1643]

Stop switching between people and just let me watch the can blow up or whatever already..

[u/rseasmith]

I always forget the British pronounce it ME-thane

[u/echimp]

Im looking for methane phase diagrams, turns out the are pretty hard to come by

[u/mitchandre]

Arrrggg.....

Lighting methane bubbles with no lab coat on, no gloves, and hair not fully pulled back.