Fingers and Franks in the LN2

It’s a fairly easy equation: fingers + liquid nitrogen = screams + injury + scars. So whenever I did liquid nitrogen physics demos for little children, or silly adults with finger-death wishes, I would always begin my show with a warning – do not try this at home.

I thought it was simple enough. After performing close to a hundred physics outreach shows as a student and then later a staff member of the University of Arizona Physics Department and College of Science, I became pretty well-versed in how to articulate my concern for my audience’s well-being. I commenced my performances with a message and a manifestation of the power of the medium.

“You see this vat of bubbling liquid?” I’d ask with exaggeration and wide eyes. “It’s actually boiling! The air is sooooo hot compared to the nitrogen, which is –320 degrees Fahrenheit, that the nitrogen is actually turning from a liquid to a gas at this very moment. And the nitrogen is soooo cold that if you stick anything in it, like your finger, for example, it…could…shatter!” Excited oooohs and aaaaahs invariably followed, coaxed by moi as I attempted to create an air of the theatrical and mysterious.

But for the savvy folks in the audience, there was no mystery concerning what I was to do next. I held up my hand, and like any decent magician, rolled up my sleeve. Then I spun around and with my back to the audience, slipped on a plastic glove that had a half of a hot dog inside one of the finger compartments. When I turned back to the audience, I held up my hand again and displayed my “protective” glove, with the frankfurter inside wagging in the wind.

So here was the big moment – would Alaina actually dip her “finger” in the liquid nitrogen to demonstrate the power of physics? Of course the answer was always yes. I knew that any halfway respectable science aficionado must commit 100% in the name of educating the public. So with a big build-up, I ushered in the climax by sticking the cylindrical meat sausage into the fire, so to speak, and “pretending” it was actually one of my digits.

“Owww!” I screamed and cried, squirming and shaking, as the kids and adults ate up the performance with giggles, all the time knowing the magician’s secret. I usually gave it a good minute, and then removed my hand and with a flash, smashed my “finger” against the table. Gleeful shouts and applause would follow. Yipee – she shattered the frank, made it look like a finger, and gave the folks their money’s worth.

If all went well, I would move on to the next demo and maybe make some liquid nitrogen ice cream. But there have been a few shows where all did not go according to plan.

On more than one occasion, I actually would hurt myself. When I dipped my frank-laden finger into the dish of nitrogen, the liquid began to bubble even more than before, and I found myself in trouble. The cold fluid hit my unprotected skin, and though it looked like I was pretending to be in pain for the sake of the audience, I actually was suffering at the hand of science. I have the scars to prove it. They are on the knuckle of my middle finger on my right hand, at exactly the place where the hot dog bordered my body in the glove.

And there was also the time that I performed my demo in a small space with about 20 people, including five or so infants and toddlers. When I banged my hand against the desk, the tots were shocked by the sound and vision, and actually thought I had destroyed and severed my finger. Frankly, they freaked out. Above the horrified cries, I whipped out my hand and showed them that my finger was still there and no (extreme) harm had come to me, but it was too late. The image was in their heads and the damage was done. Thinking back, I am horrified myself – did I scare them away from physics forever?

By Alaina Levine

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