How Not to Make Liquid Nitrogen Ice Cream
Friday October 3, 2008
This is a photo I found on Wikipedia of some people making liquid nitrogen ice cream. I wanted to call it to your attention because it's a really dangerous way to do this project. If the liquid nitrogen splashed that guy's hands the frostbite could result in permanent damage. It's easy to spill the nitrogen because it is hard to see past the vapor.
I'm all for playing with liquid nitrogen. I'd be the first one to throw a dewar of it into a swimming pool and I'll freeze every object in sight so that I can smash it. However, it can be a dangerous material if mis-used. I'm not saying you need to go out and purchase a set of cryogenic mittens, but when you make liquid nitrogen ice cream at least wear cloth gardening gloves, ok?
Comments
Oh wow, I can NOT believe they are messing with liquid nitrogen so carelessly! Now, you say it “can be dangerous if mis-used”. I take it using it to freeze a pool and smash all the frozen stuff in sight is NOT a mis-use? >>giggle
Nah, those are totally safe applications
At least, adding liquid nitrogen to an empty pool is safe. I am sort of a hazard smashing anything, whether it’s room temperature or cryo-cold.
Although this doesn’t look terribly safe, I must say that I can be equally careless with liquid N. You can pour it on your hands as long as you don’t HOLD it in your hands or pour it for too long. It forms a layer of gas N that protects your hand. But literally, you can hold out your hand, and pour liquid N on it, and be fine, just a little chilly. A brief splash would be fine too. I’ve done it many a time.
Just don’t stick any body part into the liquid N, though, that would be bad.
I don’t know… I’ve seen people touch it and be fine, but I’ve been burned by tiny splatters from a splash. I’m cautious around nitrogen. I will admit to blowing smoke rings with dry ice.
I’ve used LN2 often in undergrad labs where I’ll quickly pour some in my hand, then let students see it dance on the floor. It’s the same with a lit candle — if you don’t allow your skin to come in static contact with it, it won’t “burn” you. Getting “burns” from LN2 splatters is always a result of static contact since you’re often unaware of it until it’s too late. I’ve also essentially given lab managers moments of pause when I pour it in my hand and quickly toss it to the floor. It’s a quick way to know how ignorant a person is about basic chemistry.