Exploding Pumpkins

By: Todd Martin
Using the season of surprise, goo and a certain exploding orange fruit for all they are worth, chemistry students at the Killeen ISD Career Center observed chemical reactions Tuesday with a Halloween flavor.

Adding a spark to a mix of water and calcium carbonate to the inside of a carved pumpkin, teacher Brooke Leone demonstrated the loud partial decomposition of the chemicals - an exploding pumpkin.

Students watched from a safe distance during the lab, which was conducted on a field outside the school.

The chemical reaction that caused a loud sound and propelled a cut-out piece of pumpkin to fly 15 or so feet through the air was once used commercially to make acetylene, a gas used in welding torches, the teacher explained.

In addition, the high school students mixed a borax solution with glue to form an ooey-gooey substance known as slime.

The slime lab showed how molecules’ shapes affect their properties. The borax mixed with the glue tethering the molecules together and causing the liquid to change to a gummy mass.

“The takeaway today is that chemical reactions come in all shapes,” Leone said, explaining that the labs gave students practice in balancing reactions and hopefully made it memorable.

Students expressed their appreciation for their teachers’ creative efforts, a practice they said is common in their chemistry class and at the Career Center.

“It was fun watching it explode,” said Sydney Elliott, a sophomore and a health science student. “It’s good that we get to move around and get to learn hands-on. I was surprised how quickly it exploded.”

“The experiment was great,” said sophomore Jensen Rodriguez Pica, an information systems student. “It showed the reaction between two chemicals. It was a good visual.”

The student said the chemical reaction wouldn’t fit within the walls of the pumpkin and came exploding outward.

Going the extra effort to teach with such creativity, he said, is effective. “It gets us motivated to learn.”