What kind of name is Tryggvi?

June 17, 2003 11:42 PM

Homemade ice cream, in 30 seconds.All you need is cream, sugar, eggs, flavorings (strawberries, vanilla, kittens, whatever your preference) and access to liquid nitrogen. And there the plan goes south, at least for me. Where can the average joe score this crucial timesaving ingredient? Seriously. Also, I want to try the cool "shatter a flower" trick that they reference.
posted by jonson (23 comments total)

Ever wish for an reverse-microwave oven when you had a warm beer?
I have...
posted by y2karl at 12:00 AM on June 18, 2003

Wonder why they never used that on Iron Chef.

There has to be a way to use liquid nitrogen in manufacturing. Maybe a microbrew-sized ice cream factory could take advantage of the process.
posted by son_of_minya at 12:22 AM on June 18, 2003

Where can the average joe score this crucial timesaving ingredient?

In my experience security at some university departments using liquid nitrogen is low. At my last place the Earth Sciences dept had two containers of it just off a main path where pretty much anyone could get at it.
posted by biffa at 1:37 AM on June 18, 2003

y2karl: 5 mins in the freezer under a bag of peas?

An ex-g/f of mine was scientist at a leukemia research lab in west London and had access to gallons of nitrogen. The favourite trick was to get a couple of pints in a polystyrene flask & just chuck the liquid down the corridor that ran thru the middle of the lab to form a sea of hissing balls that evaporated within a few seconds. Fun.

BTW, I'd have to wonder about the 'science' part of 'Popular Science' if they print things such as 'So cold that it can turn a fresh flower into a thousand shards of broken glass.'
My chemistry & biology are a bit rusty but plant to glass?
[/picky]
posted by i_cola at 1:43 AM on June 18, 2003

Several years back I wondered the same thing, jonson, and I had surprisingly good luck just checking under "cryogenics" in the yellow pages. Some snooty specialty-gas suppliers only wanted to sell to Industry, but at least one company was perfectly happy to sell to J. Random Teenager and to give advice on using a styrofoam cooler to avoid having to put down a deposit on a dewar. LN2 is pretty cheap, too.
posted by hattifattener at 1:50 AM on June 18, 2003

you can score a large dewar of the stuff on any random manhattan street corner...stupid outdated infrastructure.
posted by dorian at 1:57 AM on June 18, 2003

i've seen the flower shattering trick before. it's pretty damn cool (no pun intended). that was probably the only time i was awake during my physics class.
posted by joedan at 3:40 AM on June 18, 2003

For WMV and Quicktime movies, check this link
posted by swordfishtrombones at 4:20 AM on June 18, 2003

Security around liquid nitrogen low? Oh yeah. In grad school my friends and I used to pull all nighters frequently usually because we pissed away the day and night having fun. We got in the habit of roaming around the university looking for things to do. One of the things to do was the chemistry departments loading docks. They'd leave their empty liquid nitrogen containers but usually there was an appreciable amount of liquid nitrogen left in these things. We did all the normal things with them. My friend Kumar did the abnormal thing. He saw the thick white "steam" coming off of it and decided his hand needed to be within this stream. He was OK but his hand looked like crap, the equivalent of very bad burns. No loss of fingers, hands, thumbs or any other parts.

As for getting liquid nitrogen you can often get it from a welding supply shop. A glass thermos will do as a dewar's flask in a pinch.
posted by substrate at 4:27 AM on June 18, 2003

I wish there was the ability to edit your posts. From this post you should only use thermoses with a stainless steel shell should be used, also do not screw on the cap (which we didn't do, it just seemed like a bad idea)
posted by substrate at 4:29 AM on June 18, 2003

In the DC area you can get liquid nitrogen from a place called Robert's Oxygen. We used it to make Kaluha ice cream (which was yummy) and super-concentrated vodka shots (which were unspeakably nasty).
posted by JoanArkham at 4:36 AM on June 18, 2003

I always heard that using LN is the easiest way to break a lock (such as "The Club," or bike chains). Just pour onto the metal, and smack it with a hammer. Turns into glass and shatters (read this in Popular Larceny, so can't vouch for the turning into glass part).
posted by luser at 6:16 AM on June 18, 2003

As for getting liquid nitrogen you can often get it from a welding supply shop. A glass thermos will do as a dewar flask in a pinch.

No shop should sell you LN2 in anything but a proper dewar. You *can* use a glass thermos if you are "liberating" some from a lab, but the critically important thing is to not screw on the lid!

Proper dewars are silvered on both size of the glass, and have venting. Thermos bottles are silvered on one side, and seal tight. They'll slow down the warming of the LN2, but it'll still boil, releasing gas, increasing the pressure until the thermos bursts, spraying LN2 and glass shards around. This is bad.

LN2 isn't dangerous if you are careful and know what you are doing. If you don't have the proper gloves, don't wear gloves at all -- gloves that absorb liquid will hold the LN2 against your skin. Since LN2 has a temperature at STP of 77K (or -196 °C, or -321 °F,) this is a really bad thing. Without gloves, most of it will roll off, and the instant boiling when the LN2 hits your ~80F skin will produce a thin layer of vapor that will protect you from much of the cold (the leidenfrost effect, most commonly demonstrated by sticking your hand in a pot of molten lead. Kids, don't even think about trying that at home!

If you want to play at home, go to a gas supply house, lab, medical, welding, whatever. Explain that you want to play with a little LN2, can you rent a dewar and buy some? They'll show you some tricks, rent you the proper gear, and tell you what you need to know to safely handle the stuff.

Also, a popsicle stick, a mold, LN2 and wine lets you make winecicles pretty easily. We haven't tried scotchcicles -- yet. Of course, with the scotch and water being frozen, you won't taste the subtle flavors of the scotch. So, don't use the fine single malts, the cheap blends are ideal. May I suggest, of course, Dewar's?
posted by eriko at 6:22 AM on June 18, 2003

I worked with liquid nitrogen in college. I was initially jumpy about the stuff, having grown up watching flowers and superballs flash-frozen and shattered on "3-2-1, Contact." My boss thought I was being over-cautious and startled me by deliberately pouring the stuff over the back of his hand, without injury. Over time I learned that it takes longer than an instant to freeze something with LN2. You can indeed poke your finger into it (or pour a little over the back of your hand) without damage if you're a) quick about it, and b) not getting any on your clothes, jewelry, wristwatch, etc., although I don't advocate trying this at home.

Other fun tricks: try pouring a little from chest height out of a small dewar. It evaporates (or seems to) before it reaches the floor. Slosh some across the floor towards a wall--LN2 strikes the wall, a cloud of frosty vapor bounces back. Pour a wee dram into your tepid beverage for lots of steam and some quicky ice.

The main nitrogen storage tanks were kept locked up at my university. I had to refill a large dewar from these tanks and transport LN2 to several places, often by car. The dewars have loose-fitting lids so that vapor can escapem which means that if the thing tips over the lid pops off and you've got a spill. I was advised that if this happened in my car my first priority should be to roll down a window, before the rapidly expanding nitrogen overwhelmed the oxygen in the air.
posted by Songdog at 7:15 AM on June 18, 2003

Another interesting experiment with Liquid Nitrogen:

Freeze a couple of cans of shaving cream and cut away the can. Leave the frozen blocks of shaving cream in a friends car.

Three or four cans is generally enough to fill the car when it thaws.
posted by KnitWit at 7:43 AM on June 18, 2003

Freeze a couple of cans of shaving cream and cut away the can. Leave the frozen blocks of shaving cream in a friends car.

that is the best prank EVER. man, when one of my friends finally gets married, i'm SO going to do that....
posted by taumeson at 7:56 AM on June 18, 2003

KnitWit, that has to be the most devious and wicked thing I have heard in a while. I love it! Thanks for giving me an idea or two. :D

As others have said, you can get it easily at a welding supply store, but they will require you to have the proper equipment, and usually won't sell you a small amount. Your best bet is to get it from a university, and you don't necessarily have to pilfer it. I've asked nicely in the past, and they were pretty cool about it once they were certain I knew how to handle it and that my container was appropriate.
posted by Orb at 7:58 AM on June 18, 2003

Ah, liquid nitrogen...

It brings back so many happy memories of my childhood. My dad used to bring home 'thermoses' of the stuff (probably dewars) from work. We'd dip rubber bands in them and make them shatter.

He'd also sometimes use a drop to get rid of ticks (probably not the best idea, but it was cool!).

We also did the dipping a hot dog trick and shattered it ("That's what could happen to your FINGER!...")

You mean other kids didn't get to play with liquid nitrogen?
posted by Karmakaze at 8:17 AM on June 18, 2003

The leidenfrost effect is quite a lot of fun, you can even hold liquid nitgrogen in your mouth. A physics professor showed us this a few years ago. Blowing long streams of vapour around is a great way to scare people.

warning: do not swallow the liquid nitrogen; the gas buildup would be pretty dangerous. Don't do this if you have piercings in your mouth, they could cool much faster than your mouth; The contact between the (solid) piercing and your mouth isn't protected by the leidenfrost effect.

and remember: People who do stupid things with hazardous materials often die (but have great fun until they do)
posted by fvw at 8:19 AM on June 18, 2003

Oh, and then there were the frozen snickers bars! How could I have forgotten those?

Step 1: freeze a snickers bar in liquid N
Step 2: Smash against a table
Step 3: eat tiny shattered bits
posted by Karmakaze at 8:22 AM on June 18, 2003

1001 things to do with liquid nitrogen
posted by stefanie at 8:31 AM on June 18, 2003

The best way I've found to move LN2 (outside of the professional containers) is one of those cheap Styrofoam coolers. Poke some decent-sized holes in the top, though. You should never, NEVER keep liquid nitrogen in a closed container, as the inevitable pressure buildup can cause some rather spectacular explosive effects.

(I'll second that statement about lax LN2 security at most universities; where I work, you'll often see rows of the large cylinders just sitting in the hallway. Also, Karmakaze is dead right about the candy bar chunks.)
posted by fidelity at 9:42 AM on June 18, 2003

I was lucky enough to get to try a saltine cracker dipped in LN2 when I was a kid. Because of the leidenfrost effect, It doesn't hurt you, but it does make it possible to see your breath - just like you would on a cold day.
posted by blade at 7:04 PM on June 18, 2003