FORT WAYNE – As soon as Science Central Education Specialist Alex Hart gave the OK after completing his demonstration, a couple dozen kids from the audience, mostly between ages 2 and 8, gleefully and politely formed a line for the payoff.
Ice cream tinted green from a few drops of food coloring and frozen by liquid nitrogen was served. Upon receiving their one-scoop treat in a small plastic cup, the children sidestepped to their left to add their topping of choice. And all agreed it was pretty good.
The afternoon delight was part of Science Central’s participation in the annual Winterval celebration sponsored by the Downtown Improvement District and Fort Wayne Parks and Recreation Department.
We do this for camps and birthday parties all year long, Hart said of the ice cream making. We’re doing this because of the Winterval.
With their parents in tow, the kids found a seat in the Lincoln Financial Foundation Demo Theater on the lower level of Science Central and were greeted by Hart, who asked if anybody had ever tried liquid nitrogen ice cream. Only a few hands shot up.
I love these things, a boy from the front row chirped.
As clearly as he could to the gaggle of elementary school-age onlookers, Hart began to explain the mystery of liquid nitrogen.
Everybody take a real deep breath, he said. And hold it! And hold it! And a bunch of kids were holding their breath, until they all exhaled.
Nitrogen is this gas in the air, Alex explained. And most of that breath that you just took was nitrogen. But if we exert enough pressure and if we make it cold enough, we can make it into a liquid.
Yeah, but what does that have to do with ice cream?
Hart was getting to that.
He coaxed volunteers from the audience to help put sugar and vanilla extract into a blue bowl. He added a pint of milk and a pint of half and half. With a little swirl from a whisk, it was time for science to kick in.
So he poured a small amount of liquid nitrogen into a clear container. And kids watched it smoke into a bubble.
It’s boiling, Hart said, but it’s not on a stove. So instead of it being hot, the liquid nitrogen is cold.
Somebody guessed three degrees below zero.
It’s 320 below zero, Hart said.
Kennedy Pyck, 5, became the session’s final volunteer to help stir the ice cream. She wore a purple top, brown cowboy boots, protective goggles and orange rubber gloves. And when Hart poured, Kennedy used the whisk.
I think we’ve got it, Hart announced.
And voilÀ – ice cream, with sprinkles on the side.
How great is science?