By David Kilby, Managing Editor
CRANBURY — Dozens of children mixed science and fun by combining ice cream dough and liquid nitrogen to make ice cream in the Cranbury School cafeteria Tuesday.
The event was led by Wondergy, which is based out of Philadelphia and provides science educational entertainment for parties, assemblies, festivals and camp events.
The “CoolScience” project had children discovering many of nitrogen’s attributes before making ice cream with it.
Ken Fink, founder and president of Wondergy, began the project by explaining the attributes of water.
”Who’s been having a hot summer?” Mr. Fink said at the beginning of the project, and most of the 80 or so people present raised their hands.
”What do you do on a hot day?” he asked.
”Eat ice cream,” the children responded.
He said one thing that helps cool people down is water and explained water is very useful because it also can absorb heat very well.
As he explained this, he took a water balloon and tried to make it burst by lighting it on fire with a lighter, but it didn’t burst.
Then he used a torch that was hotter and burnt a hole in the balloon.
He did this to demonstrate the fact that when something gets hot, its molecules start going crazy because the heat gives the molecules more energy. Eventually, those energy-packed molecules burst out of whatever is containing them. In this case, it was the water bursting out of the balloon.
He explained how liquid freezes when its molecules “slow down” and heats up when its molecules “speed up.” Typically, a person would freeze ice cream by causing the molecules in the milk and cream to slowly slow down in a freezer, which takes hours.
He said nitrogen does practically the same thing, just “a heck of a lot quicker.”
”It’s so lightly bonded that the molecules easily break apart,” he said.
The boiling point of nitrogen is –320 F, he explained, so it begins to freeze anything above that temperature that absorbs it.
After the water balloon’s water leaked out all over the children and the floor, Sarah Wanger, “mission control and chief scientist” for Wondergy, asked the children if they wanted to wait and watch the water evaporate.
”It’s not very exciting to watch water dry up, is it?” Ms. Wanger said. “It just so happens that we brought something with us that dries up much faster than water.”
She and Mr. Fink walked around the room with a beaker of liquid nitrogen and told people to blow on it.
They dumped it on a carpet, and it rapidly disappeared. When they asked where it went, some children said it evaporated into the air, and others said the carpet absorbed it.
They further demonstrated the qualities of nitrogen by attempting to cover a bottle of it with a balloon.
As they left the bottle alone, thinking everything was OK, the children pointed to it and tried to tell the scientists the nitrogen was inflating the balloon, and the balloon was about to burst.
”Why does it stretch the balloon out?” Mr. Fink then asked.
It was because the molecules of the nitrogen are more loosely bonded than that of water, for example, so it takes less for them to break apart and expand, he explained.
”What if you were inside the balloon, what would you bump into? The rubber,” he said, as he explained what the nitrogen molecules were doing inside the balloon.
After using the nitrogen to inflate a balloon, Mr. Fink and Ms. Wanger used the nitrogen to shrink a few balloons.
They did this by dumping nitrogen into a “toy chest” that originally was too small to fit their inflated balloons within. But as they placed the balloons in the nitrogen-filled chest, the balloons shrunk.
”Don’t you wish you had this stuff when you were packing for vacation?” Mr. Fink said.
Then they took the balloons out of the chest, and they began to naturally inflate again and returned to their former size. The coldness of the nitrogen caused the balloons to shrink, but the heat in the air made them heat up and expand again.
They did this to demonstrate what will happen to the molecules of the ice cream dough once they pour liquid nitrogen on it.
Without further ado, Mr. Fink and Ms. Wanger began to make ice cream with the children by pouring heavy cream, whole milk and sugar into a large bowl.
A winning majority wanted cookies and cream ice cream so they poured vanilla and Oreo cookies into the bowl and mixed it up.
”We could just stick it in the freezer now,” Mr. Fink then said. “Why shouldn’t we do that? Because it’ll take too long. Who wants ice cream in three hours?”
He then took out his nitrogen tank and began pouring the nitrogen on the ice cream dough.
”More than three-fourths of the air is this stuff — dried-up nitrogen. It’s going to steal all of the heat from the ice cream,” he said as he began to mix.
Within minutes, the heavy cream, milk, sugar, vanilla and Oreo cookies thickened into ice cream, and everyone lined up to get a cone or cup of it.
Wondergy has done this project all around New Jersey, Pennsylvania and New York and has gone as far as India with the project.
The entertainers began at birthday parties.
”When we do it for a school, they say it’s the most educational program. When we do it for a party, they say it’s the most fun program,” Mr. Fink said. “This is having fun figuring out how things work out because people are intrinsically curious.”
”I think the best thing was that everyone got an ice cream cone,” said Jan Murphy, coordinator of the library’s children’s program. “So the kids really got a lot out of it.”
She added, “I think he did a good job explaining it at their level.”
”The more you know how stuff works, the more you can do with it,” Mr. Fink said.
”It was like a science class, but it was fun,” said Gabe Nydicke, a child who attended the project.
For more information on Wondergy, visit www.wondergy.com.