Sibley High teacher captures physics on film

For Peter Bohacek, the secret to teaching one of the most abstract and challenging high school subjects — physics — is remarkably simple.

As a teacher at Henry Sibley High School, he creates videos of everyday situations that demonstrate a physics concept and lets students do the rest.

"Physics has always been taught with word problems," said Bohacek, a physics teacher for 12 years. "But physics isn't about words, it's about events."

On a Tuesday morning, Bohacek shows students a video he made of a toy airplane, attached to a string and flying around in a circle. The half-moon shape of a protractor is superimposed on the screen, along with a counter giving the number of frames per second and a gauge measuring the string's tension.

With all the necessary information on screen to make measurements, students can watch the videos multiple times and determine how to answer questions such as: What's the plane's mass? How fast is it going?

Though basic, the videos push students in a way that word problems cannot, Bohacek said. "At first, [the videos] are really challenging because students aren't used to learning this way. They're used to being given all the relevant information," he said.

So far, he's shot 50 of these "Direct Measurement" videos. He shares them with other teachers on YouTube — his channel gets 3,000 hits a month — and on the Science Education Resource Center (SERC) website run through Carleton College.

Like other physics teachers, Bohacek has been showing physics videos in class for a while, but his passion for Direct Measurement videos began four years ago. He and his collaborators are among a handful of educators nationally making them, he said.

The videos aren't new. They have roots in the 1960s, when a series of "brilliantly-directed" videos were made, he said. Now, they're "almost completely forgotten."

Teachers also use labs to give students hands-on experiences, thought to be the "gold standard" in science education. But sometimes they don't go as planned or allow students to make all the measurements they need in a short time, he said.

"The other thing is, what if you're a teacher that doesn't have that stuff?" Bohacek asked.

Direct Measurement videos are often better, because they require students to be active learners and pose their own questions, Bohacek said.

Seeing things on screen "makes it real for them," said Rebekah Johnson, another Sibley High physics teacher. When watching videos, students are creative and engaged, looking at situations critically to see what's actually happening.

"I think that must translate out in the world, to look at things that way," she said.

In the summer of 2012, the district purchased upgraded cameras so he could make higher-quality videos, he said. The NSF grant will fund even nicer equipment, he said.

Making the videos is "surprisingly hard," he said. "It's hours upon hours."

In the airplane video, for instance, it took three weeks of filming to get the angles just right. Then there are "real-world complications," like when the ice kept melting under a car being driven in an outdoor friction demonstration, he said.

He's had interest from several universities, including the University of Minnesota, that want to use the videos, he said. He also licenses videos and accompanying lesson plans to an online provider of math and science assessments.

Teachers, too, send him e-mails offering encouragement or suggestions, he said.

"And they get used," he said. "That thrilled me, the idea that a teacher said, 'This is what I'm going to have my students work on today.' "

Erin Adler • 952-746-3283