A 15-pound bowling ball is attached to a large string in a nearly empty room. A man holding the ball at one end of the room releases it. The ball begins its arc. As it swings back like a pendulum, the ball seems destined to smash into the man's head. Just before it reaches his skull, the ball stops and begins its swing back. Although the scene makes you wince, it's hard to look away. This is more than an odd stunt video on the Internet. This is a physics lesson for students at the University of Minnesota at Crookston. The man in the video is their professor, calmly proving a principle of motion and force.
Beyond paper and chalk
Two years ago, David DeMuth, an assistant professor of physics and math, brainstormed about how he could use the Internet in his teachings as an ancillary tool. "I like chalkboards and impromptu learning, but the scientist in me likes to custom build ancillaries so students can get to things at any time," says DeMuth. Now that most students have laptop computers, he wanted a way to deliver those ancillaries by computer.
As a result, DeMuth and a colleague began putting together video clips for the class Web site. The bowling ball video serves as an example of the conservation of energy. Since his classroom wouldn't accommodate hooking a bowling ball to a ceiling, DeMuth had the experiment filmed and loaded onto the Web.
More importantly, DeMuth made sure the scene was filmed from a variety of viewpoints. "On one screen, students can see a close shot of the ball leaving my face, another shows a side view of the whole room and another box shows the bowling ball's viewpoint," he explains. The shots illustrate the concept in ways students wouldn't be able to see closely or simultaneously if they were watching the experiment in person. They can click to repeat the video clip on their own computer and can see the concepts of the forces acting on the bowling ball and understand why it will not hit DeMuth's face.
DeMuth also worked with PERL (practical extraction and report language) script and SQL (structured query language) databases to add online quizzes and homework modules for students. Before creating the quizzes, he knew he wanted to avoid the multiple-choice format. "I'm not sure it's helpful," DeMuth says. "Plus, I've seen some low-tech code done on a browser, where, if you view the source code, you can see the answers." The quizzes and homework assignments are usually taken directly from the textbook but are coded so that when the page is refreshed, the questions change slightly. "I do monitor the databases to see how students are doing, and how much time they spent on a question," says DeMuth. The tests are automatically graded and students get instant feedback. Also, they can return to retake quizzes whenever they want. All DeMuth's lessons are also online in a PDF format.
He doesn't claim his approach is new or Nobel Prize-worthy, simply a more intriguing way to prepare students ahead of time. "If I'm going to be teaching about forces, I like students to at least have seen an example of that," DeMuth says. Students can come to class somewhat prepared, and he can make better use of their short classes, since extra time won't be spent on more rudimentary principles.
To DeMuth, you can't learn and understand physics unless you can also see the principles. "The students may find my methods a pain in the ass sometimes, but I think they appreciate that they have to do this," he comments. "I know I do, for it keeps me in line, too." The next step for the professor is to measure his methodology to prove whether it works and adds value. To do so will require a lot of data, which may take a year or two to compile. For a scientist, though, it's an experiment worth doing.