Liquid Nitrogen Experiments: Insulators

[aurestest]

Great teaching guys

[DomR1997]

If I had liquid nitrogen I would just put stuff in it all day. Balloons, pencils, rocks just random stuff.

[oclax15]

What it be too much to ask for for one of you two to demonstrate the liedenfrost effect?

[btfu62]

Nice experiment, but you forgot to take into account the geometry of the cups. If they have different surface area to volume ratios then they will most likely have different rates of heat transfer

[JeffersonLab]

@btfu62 Yeah, but the surface area to volume ratios aren't different by an order of magnitude. 36% of the water froze in one cup and 0% in the other. That's difficult to explain with such a small difference in surface area to volume ratios. It does matter, it just doesn't matter that much here.

[falconet1234]

Were there not some variables other than the manipulated variable that changed? (thickness of the cup, size of cup)

[JeffersonLab]

@falconet1234 I'm sure if you measured the cups carefully, you'd detect a change. It would be largely unimportant, though.

[littlebigheroman]

The foam cup was a better insulator because of the dead air space in the foam cells.

[BradySayre]

I thought you were not supposed to consume a science experiment.

[JeffersonLab]

@BradySayre In general, no. But, we know it's just water in the cups and we didn't add anything to it, so it's still just water.

Guess it's a good thing we didn't call our making of liquid nitrogen ice cream an experiment!

[BradySayre]

@JeffersonLab Wow thanks for the reply. I know it was just water:) but you know how some people are. Hope you make lots mors experiments. Have a nice day.

[Singetally]

@BradySayre That doesn't make any sense...why cant you?...If you do an experiment involving gummy bears and you keep them edible, then you cannot eat them at the end?...

[gigityman2]

is the ice safe to use to cool drinks?

[JeffersonLab]

@gigityman2 For the most part, yes. It's possible to end up with ice that's cold enough to be dangerous. In this case, there was still liquid water in the cup along with the ice. That tells us that the leading edge of the ice is just barely freeing. The stuff to be careful with is the ice closest to the nitrogen. That could be dangerously below freezing.

[bigeyezzzzzzz]

What a cool experiment! I'd sure like to understand more of the science behind the experiment....like why you chose liquid nitrogen to use instead of anything else, and what are scientific reasons are for the water levels dropping in differing cups. If you have time to reply, I'd sure love to fully understand the experiment.

[JeffersonLab]

@bigeyezzzzzzz We used liquid nitrogen mainly because we have a lot of it, so we might as well use it. Also, the water levels in the cups didn't change. The water that was in the cup that was the good insulator didn't freeze while some of the water in the other cup did. So, same amount of water in both cups, but it was all liquid in one cup and partly frozen in the other.

[bigeyezzzzzzz]

@JeffersonLab Thanks for replying! Would it be safe to do this experiment using styrofoam cups, and also those cups made from cornstarch "styrofoam"? Also, what are the bowls made of? Thanks again...!

[JeffersonLab]

@bigeyezzzzzzz Yep. Not a problem to use styrofoam cups. The bowls... styrofoam!

[bigeyezzzzzzz]

@JeffersonLab Thank you!! Now we just have to figure out a way to bring some liquid nitrogen home from the local welding supply company. Other than buying a Dewar, do you have suggestions for safe ways to transport small amounts of the stuff?

[JeffersonLab]

@bigeyezzzzzzz The cheap-o styrofoam coolers aren't too bad. The main danger is if the nitrogen spills over if it is inside your car. It won't freeze you. It'll change to a gas and lower the oxygen concentration in the car, causing the driver to pass out and the car to go wherever it wants to go. Because of this (something we call ODH - Oxygen Deficiency Hazard) you really should carry it around in the back of a pick-up truck.

[bigeyezzzzzzz]

@JeffersonLab As it's probably not desirable to drive while passed out, we will take your suggestion and attempt to find a pickup truck. Alternatively, as long as we're getting the liquid nitrogen at a welding supply store, we could ask them to fire up their torches and cut the top off of our car. It's nice to have options!! Thanks again for all your time and help...we'll see how it all goes!

[dorkhawky]

i like how you clearly explain the demonstrations without interfering with the action! keep up the good work

[MrMontez11]

I don't know why, but the fact that one can just pour liquid nitrogen anywhere and it just boils away and doesn't get anything wet really amuses me :)

[ChowderMania2]

GO RIGHT CUP! :3

[XsuzyX97]

this is super cool!

[Panjaquomi]

I love how thorough you folks are with each of your experiments. Some people think that it's over the top - and in some cases, they're right. In the end, however, you easily explain the phenomenon that you're experimenting with, which is the goal of any instructional video.

[bu22cola]

Why would you drink your water like that? what if some of the liquid nitrogen got inside the cup?

[JeffersonLab]

Because it's refreshing!

Remember, the cup went in the nitrogen. The nitrogen didn't go in the cup. All we ended up with was cold water.

If enough nitrogen had accidentally gotten into the cup for Steve to have noticed, he wouldn't have drank it.

[damoos]

And this folks is the reason why hot coffee is more likely to be served in a Styrofoam cup rather than a clear plastic cup. I wouldn't fancy holding one of them with my morning piping hot beverage :-)

[lexnalyceTV]

This totaly helped me with my science, and i have a huge test tomorrow! thnx!

[Mafiacowz]

this seems too educational... goodbye LOL

[JeffersonLab]

Sorry. It's hard to judge the right amount of educational. Thanks for stopping by...

[ihavenospaces]

i really liked this video. I think it is the perfect amount of educational/ coolness

[ihavenospaces]

i thought it was both educational and interesting

[DaCaSh100]

WOW great job! that was really interesting

[pulehest]

hey you the lady you have 2 white cups not one soo you got a bether isolator becoase that

[JeffersonLab]

No, Joanna only has one styrofoam cup.

[ihavenospaces]

Does the styrofoam cuf insolate hot things as well as it does with cold? when i have hot things in styrofoam, it seems barely able to stop the heat.

[JeffersonLab]

It should work for hot things as well as cold, as long as the hot thing isn't so hot that it damages or melts the cup. It really the difference in temperature that matters. Maybe your styrofoam cups are unusually thin?

[ClairissaJill]

Hey, that was neat! My class and I are conducting an experiment in which we have to insulate a plastic container so that an ice does not melt as much as it would without the insulation. That helped a lot! =D

[bestSVMS]

you could have just tested how foggy each got

[JeffersonLab]

Maybe, but that's a bit difficult to measure. We also could have measured the temperature of the water, but seeing how much water froze is (in my opinion) more interesting that looking at a number on a thermometer.