Why does ice melt faster in water than in air? Which is hotter, white fire or blue fire? How does a liquid crystal display monitor work? Why is the sky blue? Does tapping the top of an unopened soda container reduce the risk of "soda explosion?" What is the shape of a raindrop? Why do ships float? What state of matter is Jell-O? How do tornadoes begin? Why does a compass always point north? What causes a tennis ball to lose its bounce? Is air pressure stronger than water pressure? What is a simple experiment pertaining to Bernoulli’s Theorem? How does reflection occur?

Life is full of questions that can be answered with physics that even a grade-schooler can understand. Dispelling the notion that physics is just for egghead scientists, students with the University of Illinois Physics Van outreach program are proving that everyone can understand and use physics.

These U of I students take a traveling science show to schools within a 60-mile radius from the Urbana-Champaign campus to show kindergarten through sixth-grade children the wonders of science. The experiments are a little wild (the soap explosion) and a little wacky (the banana hammer), and many should never be tried at home (whipping a tablecloth out from under dishes), but they all illustrate basic physics principles related to states of matter, Newton’s laws, electricity, sound, air, and light.

"We want to show that science is exciting and also that it’s not hard," said Tamara Gossman, an animal sciences major and student coordinator for the Physics Van project. "There’s a lot of fear of physics out there. People don’t think they’re smart enough, but that’s not true. If you know that an object will fall when it’s dropped, then you already know something about physics.

"We try to make sure everyone understands what’s happening so that even if they don’t remember the details of how an experiment worked, they’ll remember the feeling of having understood science."

Gossman is one of nearly 30 students from around campus participating in the Physics Van project. Many of the students, including Gossman, signed on after seeing Professor Mats Selen blow up something in an introductory physics class. Selen helped develop the Physics Van project in the mid-1990s and now advises the student team.

"I’m good at blowing things up," Selen admitted, adding that the best students for this project are the ones who "never quite grow out of playing with stuff. They like to explain how things work. They’re the kind of students you hope your own kids will turn into."

Nurturing a Love for Science

The idea for a traveling science show was originated as a way to reinforce the ideas that science is fun and that anyone can do it, Selen said.

"Young kids love science," he said, "but something happens around middle school and by high school, they’ve lost interest or think it’s too hard. We want to show them exciting experiments done by a broad spectrum of students—women and men, different races—all having a great time doing science. We want them to come away with the idea that science is cool and it’s something they can do. It’s not just for a guy with funny glasses.

"So if they’re curious at all—if they wonder why the sky is blue—then they’re already scientists, and they can keep thinking that way, and they can do it because the students in front of them did it. It’s an attitude we want to convey."

The Physics Van team typically performs for all-school assemblies, which can be as many as 500 children. They also serve smaller venues, such as camps, boys and girls clubs, and science fairs, and they make special appearances at Chicago museums, the Illinois State Fair, and other locations. Each spring they partner with the Physics Society to showcase science at the annual Engineering Open House on the U of I campus.

Explosions and Other Hair-Raising Physics

Just back from a show at the Ogden Elementary School and still wearing parts of a 15-foot soap explosion experiment, Dan Kiefer, a math and physics major, said it was difficult to know who had more fun—the U of I students, the school children, or the teachers. "It’s fun to show kids science," he said, "and it helps me understand the concepts better when I have to explain them. This is a great experience for all of us."

The Physics Department has a history of using experiments in lecture classes, and some of those, along with experiments performed at Engineering Open House, are the basis for the Physics Van repertoire. Students can choose from more than a dozen experiments that have proven easy to transport, safe to perform, and popular with the younger crowd. They can also suggest a new experiment. "We’re a work in progress," Kiefer noted, "and I think that’s one of the appeals."

According to Kiefer and Gossman, the Ogden Elementary students liked the soap explosion—saved for the finale—best. This experiment illustrated state-of-matter change. Kiefer dumped a vat of liquid nitrogen into a bucket of soapy water. Colder than the water, the liquid nitrogen evaporated, producing gaseous nitrogen that formed expanding bubbles in the soapy water.

"The explosion was rather impressive," Kiefer said, noting that any experiment with liquid nitrogen elicits an "ooh, ahh" response and questions about where to find the material. One of his favorites is the liquid nitrogen cannon. As liquid nitrogen in a metal cannon warms, it expands until it pops the cork used to contain it. Another crowd-pleaser is the team’s banana hammer invention. Dipped in liquid nitrogen, the banana undergoes a state-of-matter transformation as the water in it freezes and the banana becomes hard enough to hammer a nail.

Also popular is the Van de Graff generator, which separates positive and negative charges. In one demonstration, a person touching one of the domes collects only one type of charge for a momentary bad-hair experience, which is good not just for laughs, but also to show that same-charged hair strands repel each other.

Physics Is for Everyone