Chemistry explosion

CHILDREN WATCH WITH amazement as Middlebury College students make ice cream using liquid nitrogen during the Mr. Wizard Chemistry Show in Bicentennial Hall last Friday night. The college will host an encore performance of the popular event on Feb. 29.
Independent photo/Trent Campbell
January 18, 2008
MIDDLEBURY — At Middlebury College’s Mr. Wizard Chemistry Show last Friday, the children in the room, scattered throughout the overflowing audience at first, gradually got out of their seats and drew closer to the front of the room where five chemistry majors were concocting a magical treat. Dressed in lab coats and safety goggles, the students had filled two bowls with heavy cream, sugar and chocolate sauce and were topping off the mixture with a constant stream of liquid nitrogen.
“The kids were just like molecules extracted from the audience,” noticed retired chemist and Vergennes resident Margaret Lowe, who had come to the show with her husband, Steve, also a retired chemist.
In a night of chemistry magic featuring color-changing liquids, eruptions of “elephant toothpaste” and no shortage of explosions, the liquid nitrogen ice cream was the biggest hit.
Like all of the experiments that night, the ice cream served to teach the kids about chemistry in a fun way they would remember. The college’s Mr. Wizard shows in the past have been a little wilder — with a few more unpredictable flames — but this year, chemistry professor Roger Sandwick geared the event, which was held in the college’s Bicentennial Hall, toward younger children.
“We’re pitching this at a third-grade level, so probably it will be at the appropriate level for some of the adults as well,” he said.
The show was inspired by the experiments that had captured Sandwick’s imagination as a child. “We used to have this one guy — we called him Mr. Chemistry, he was probably about 80 years old — who would come to our class and do all these magic tricks using chemistry,” he said. “It’s the one thing I really remember from that particular third-grade class.”
If the response from the children who attended Friday’s show is any indication, these kids aren’t likely to forget the experiments, either. The evening began with kids shooting their hands up and squealing to be picked as volunteers and ended, two hours later, with them waving and standing on their chairs to be part of the action.
Some people could not squeeze into the crowded room for the show, so the college is planning an encore performance for Friday, Feb. 29, at 6:30 p.m., at Bicentennial Hall.
 In one experiment, junior biochemistry major Annie Onishi asked everyone to close their eyes and imagine what they would do if they were outside in a snowstorm together in shorts and t-shirts. Huddle, everyone said. What would they do if they were dressed in their warmest snowsuits on the fourth of July? Take it off, someone suggested.
Onishi said, well, actually you’d spread out first.
“Guess what? Molecules do the exact same thing as people,” Onishi said. “They come together when they are cold and spread out when they are hot.”
To illustrate her point, Onishi filled a bottle with a drop of “Professor Roger Sandwick’s special sauce,” which was actually methanol. She held up a long lighter and asked for a volunteer. Hands shot up.
After suiting up in a special tye-die lab coat and oversize goggles, Elias, the volunteer, put the lighter in the bottle and lit it. The cork blew off, hitting the ceiling, and the whole room cheered.
Onishi explained that when Elias lit the flame, the liquid transformed from a liquid to a gas, and the molecules separating pushed out the cork.
In another experiment, junior Kevin O’Rourke filled an empty egg shell with hydrogen gas. As he passed a lighter to Bailey, a new volunteer, Sandwick carefully took the giant tank of hydrogen away. The parents cheered.
When Bailey lit the egg, it exploded. O’Rourke asked the kids if they wanted to fill something bigger. Someone suggested a basketball and Steve Lowe, the other retired chemist in the audience, said, “Remember the Hindenburg.”
O’Rourke offered an explanation everyone could understand.
“When hydrogen molecules and oxygen molecules get together in a close space and they get a little starter from the match, they tend to like each other so much that they explode,” he said.
The experiments were more explosive after that. O’Rourke filled soap bubbles with hydrogen, and let volunteers light them into fireballs, and another student created an enormous glowing “spiral of energy” with the luminescent combination of bleach and luminal.
In the audience, the retired chemists were nearly as excited as the kids.
“We became chemists because we had chemistry sets as kids,” Steve said.
Margaret added that chemistry sets were a staple in the childhoods of most of the chemists in her generation. “They’ve made them so safe these days that they’re not nearly as fun,” she said.

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