Liquid Nitrogen vs. Liquid Oxygen: Behind the Scenes

[ivandefr]

if they spill the liguid nitrogen and the O2 drop to 19.5%  ... they could "accidentally" spill some liquid oxygen to raise it back up again :P

[newcoolvid27]

Where will I find this video?

[JeffersonLab]

@newcoolvid27 Which video?

[hotpockets222]

@JeffersonLab this is the behind the scenes, but where's tthe video?

[JeffersonLab]

@hotpockets222 Look for the ones called 'Liquid Nitrogen vs. Liquid Oxygen: Magnetism' and 'Liquid Nitrogen vs. Liquid Oxygen: Fire'.

[Almontmarine]

do you rehearse for your videos or just start directly?

[JeffersonLab]

@Almontmarine If time allows, we like to rehearse a day or two before we're scheduled to tape. It doesn't always work out that way, though. Usually, the taping goes faster/smoother when we can rehearse.

[Almontmarine]

but in the end both of you filmed three right?

[JeffersonLab]

@Almontmarine Actually, no. The third experiment we had planned didn't work out as we had hoped, so we scrapped it.

[MegaTories]

19.5% O2 as a cutoff seems a little over-cautious. Jefferson Lab is virtually at sea level, right? So by my reckoning, in terms of partial pressure of oxygen that's equivalent to an altitude of about 570m. A cutoff of 17% would give a similar O2 partial pressure to a passenger aircraft fuselage or on the ground in Boulder, Colorado.

[JeffersonLab]

@MegaTories It's intentionally over-cautious. You don't start getting health effects until you're around the 17% level and those are rather trivial (increased respiration, increased heart rate, reduced night vision) assuming you are already in good health. But, that's the whole point. Get people out before you're anywhere near real trouble. It's not just us, though. 19.5% is an industry standard.

[MegaTories]

@JeffersonLab Thanks. Does that 19.5% industry standard vary with altitude at all? Or is it still the same if you play with LN2 in a tent in the Himalayas? ;-)

[JeffersonLab]

@MegaTories That's actually an interesting question that I don't know the answer to. Hauling nitrogen up Everest is a bit extreme, but one of our sister labs is out in Colorado. I assume that they play by the same 19.5% rule book that we do. I'll have to ask them...

[Snakecharmer95]

have you ever mixed together liquid nitrogen and liquid oxygen or would that be dangerous?

[JeffersonLab]

@Snakecharmer95 If you mix liquid nitrogen with liquid oxygen in a 78:21 ratio, you just end up with liquefied air. If you watch one of our very first videos, we put a balloon in liquid nitrogen and change the air inside of it into a liquid. That particular mix isn't especially dangerous. You can run into problems if the proportion of liquid oxygen gets too high, though.

[meowmeow5]

there is an easier way to collect liquid oxygen, get a heat proof beaker, mix some 20ml 30% hydrogen peroxide and some potassium iodide in there and put a balloon on it, as soon as its inflated, close the balloon and put a test tube over the base and cool the balloon down with liquid nitrogen, hey presto, instant liquid oxygen, and also you would not need to filter it as its pure already.

[JeffersonLab]

@meowmeow5 Yes, except we aren't a chemistry lab. We don't have potassium iodide on the shelf. We do have small oxygen tanks for welding and lots of liquid nitrogen, so our method worked for us considering what we had available.

[Ek0shi]

It's nice to see the human emotion in these videos as somewhat opposed to your other scripted videos.

[JeffersonLab]

Yeah...

If we could ad lib everything, that would be great. The thing is, there are certain points that we want to get across in each video and it's too easy to either (a) forget one, or (b) blather on about some trivial point. For example, we wanted to point out the fire blanket on the table, but forgot to. At best, we get a few hours a month to film. Scripting helps us get the most done in the limited time we have. We don't always stay on script, but it's a good starting point.

[NoWattz]

It's good that you took time to emphasize the importance of saftey. Just as you'd said, saftey is an issue that isn't very prevalent here on youtube. So, much applause to you n' your crew for doing things right. :) Nice vidZ!