Visiting an elementary school, College of Science students demonstrate musical fire.

Playing with Fire and Ice – and Potatoes

UI class shows fifth-grade students the fun of science

By Holly Bowen
Reprinted with permission from the Moscow-Pullman Daily News

The forecast Monday afternoon at Lena Whitmore Elementary School in Moscow was partly cloudy with a chance of potatoes.

Brian Morra, a senior geology major at the University of Idaho, crammed a whole red potato into the open end of a plastic pipe as he turned a valve on the pipe to release excess air. After the potato was securely in place, Morra attached the hose of an air compressor to another segment of pipe and filled it to capacity.

"Later, tater," Morra said as he released the pressure, causing the potato to rocket forward and slam against the brick exterior wall of the school. The potato instantly broke up into hundreds of tiny pieces that rained down over a class of fifth-graders who were gathered nearby.

More than a dozen students in associate professor Karen Harpp's geoscience education and outreach methods class spent this semester developing interactive activities to introduce youth to basic scientific concepts. Several of them visited Lena Whitmore Elementary School for the second time Monday.

Harpp, who funded the service-learning class with a seed grant from the UI, said she assisted her students and gave them information about how to work with different ages of children, but they were largely responsible for researching, designing and building the activities on their own.

"The hardest part about an outreach program is getting it rolling," she said, adding that the high level of student involvement in this case mitigated that issue.

The fifth-graders split into three groups to rotate through sets of activities led by the university students.

Morra and Kirsten March, another senior geology major, led the younger students in a few demonstrations of air pressure. They explained how during times of high pressure, air molecules become packed tightly together, like when the air compressor filled the potato launcher with its "fuel."

Inside one of the classrooms, Omar Davalos and Jen Lennon, both senior geography majors, taught students about sound waves and frequencies with a handful of activities that called for the use of Slinkies, balloons and glass soda bottles. But the final sound wave activity is likely the one that will burn bright in students' memories.

Davalos hooked up an electric guitar to a Rubens' tube, which is a long metal pipe with holes drilled in the top. Propane gas flows through the tube and is lit on fire as it passes through the holes. As Davalos played notes and riffs on the guitar, the flames coming out of the tube rose and fell along with the sound.

Students and teachers in the room burst into laughter when one of the fifth-graders began singing "Eye of the Tiger" by Survivor into a microphone that was attached to the Rubens' tube, causing the flames to dance up and down with the fluctuations of his voice.

For the final moments of the day, students gathered outside to test a homemade hovercraft and witness a pair of garbage cans exploding under pressure.

The hovercraft, made out of plywood, plastic sheeting and a leaf blower, used a cushion of air to lift the plywood platform slightly off the ground. The younger students stood on the hovercraft and slid around on the pavement with the help of their older counterparts.

"You get to float on air," fifth-grader Cylestte Williams said after taking a spin on the hovercraft. "It's so fun. You kind of get to surf on it."

Her classmate Tyler Davis agreed that the hovercraft was his favorite part of the day, but he was also excited to see the exploding garbage cans.

During that experiment, the university students filled a two-liter soda bottle with liquid nitrogen and then placed the bottle into a garbage can filled with water. After a few seconds, the bottle exploded inside the can, which also exploded and sent water flying everywhere, including all over the students. They exploded two garbage cans by the day's end.

"The nitrogen got all pressurized inside the bottle," Davis explained. "When they threw it into the water, it got colder and colder and exploded."

"It just couldn't take it," Williams added with a sympathetic shake of her head.

Judy Mock, one of the fifth-grade teachers at Lena Whitmore Elementary School, said the students were so excited about the UI class' first visit that they invited them back for Monday's second round of activities.

"It's so nice for them to be able to see applications of the things they're learning in science," she said.

Just before the fifth-graders were sent home for the afternoon, the UI students treated them to their final activity of the day - eating ice cream made by mixing cream and liquid nitrogen together.