Liquid nitrogen proves amazing
BUFFALO TWP — Freeport Middle School sixth graders on Friday were treated to a live demonstration of the surprising effects liquid nitrogen can have on everyday objects.
Visiting scientist Lawrence Kupchella made a presentation to Freeport Middle School sixth grade students called, “The Amazing Properties of Liquid Nitrogen.”
Students learned about the three stages of matter and what happens when they are exposed to extreme temperature changes.
After quickly quizzing the students on some chemistry, Kupchella filled two containers with liquid nitrogen. The students applauded when he tossed some on a curtain by the stage, evaporating too quickly too stick to the fabric.
Kupchella explained that just as water boils when heated, so too does liquid nitrogen, except this liquid boils much easier than water: Anything hotter than negative-320 degrees Fahrenheit.
“There's nowhere on Earth that I could pour this out and it will not boil,” he said. The steady stream of vapor pouring from the containers confirmed this.
Next he produced a rose and submerged it in the liquid, “like a red hot poker in water,” he said. Anything can heat up liquid nitrogen.
The audience gasped when Kupchella took the rose in his fingers and shattered it. A few seconds later, Kupchella showed that what was left of the petals was again soft and flexible.
“Why did that happen?” he asked. Dozens of hands went up as the young scientists put forth their guesses.
“Because the flower has water in it?” one student asked.
“That's exactly it,” Kupchella said.
Throughout the presentation Kupchella submerged several common objects from balloons and rubber balls to paper and even his own necktie, showing how each reacts and also how some objects don't at all.
Before each he encouraged the students to draw on their knowledge and try to anticipate the results coming from the metallic canister beside him.Students learned about molecular motion when Kupchella imploded a rubber ball that had been submerged. He jotted a quick illustration on the white board about how temperatures affect the speed of air molecules.Kupchella impressed the class by hammering a nail into a board with an apple and showed how you can inflate a balloon with a beaker and boiling nitrogen.“That was one of the coolest (series of) experiments I've ever seen,” said Hadley Hellgren, a sixth grader. “I was expecting just a regular science experiment.”Kupchella is a chemistry professor at Indiana (Pa.) University and is also the Visiting Scientist Program director at the university.“The science teachers in our local schools without question do an outstanding job of educating the K-12 students,” Kupchella said. “Our program is designed to augment their efforts by demonstrating aspects of science that are out of reach of these teachers.”The Visiting Scientist Program is funded in large part by the Society for Analytical Chemists of Pittsburgh.
