ScienceWise - Summer 2013

Hitting the marks

A novel teaching method that really produces results

Physics is not the easiest of disciplines to study. It requires a strong maths background, excellent logical deduction skills and a lot of background knowledge. But physics is an essential requirement for engineering and many other applied sciences. So how do you go about teaching something like physics to students with a huge range of abilities and levels of enthusiasm for the subject?

This is precisely the dilemma of Dr Paul Francis, one of the scientists at ANU responsible for teaching physics to 270 first year undergraduates.  “In approaching a physics problem, there are a few things that really get you off on the right track,” He says, “Drawing a good diagram that contains all the essential elements, adding description so that you clearly understand where the equations and calculations relate to the problem and finally checking your answer to see that it’s in the ball park of what you would expect.”

“In spite of going over these points time and time in the lectures we were finding that in the final exams not every student drew diagrams, very few used descriptions and almost none ever checked that their answers were even remotely plausible. Every year we make adjustments to the course to try and improve this and we monitor the results. Some things make a little difference, some none. But every now and again we come across an idea that has a profound effect.”

In this case the profound difference came in the form of old ideas and new technology. “We had always asked the students to solve homework problems,” Dr Francis says, “But they weren’t working nearly as well as they should and we believe this is due to what psychologists call cognitive load theory.” Essentially cognitive overload occurs when trying to learn something new and being overwhelmed by all the different components that need to be grasped at once. Rather like learning to drive a car. If you’ve never driven before steering, indicating, gear changing, obeying road rules and watching the other cars results in a truly dreadful experience for driver and instructor alike.

When doing a homework physics problem the students have to typically keep in mind two or three different physical principles, the application of these principles to this particular problem, several mathematical tricks, and also keep an eye on the big picture of what they are trying to achieve. No problem if you’re Einstein, but a bit much for a novice who isn’t completely fluent in the basics.

The solution was to do the worked examples on an ipad using the “Explain Anything” app and to post these online so that the students could study them in their own time and at their own pace rather than the frantic scribbling in the lecture. “One of the key things is that I did each worked example cold,” Dr Francis explains, “So I would draw things up make mistakes, cross things out and go back just like we do in real scientific research. I’d explain why I was using each equation rather than just plucking one from the air as many of the students were doing in the exams and at the end I’d check my answers. So if I got the radius of the earth to be 25cm I’d know there’d been a mistake in the calculation and go back, again just like we do in real science.”

The results were remarkable. In the first exams after the introducing of the online worked examples, almost all the students were constructing good diagrams of the problem, explaining their workings and checking that their answers were at least vaguely sensible. “It’s not often in teaching that we come across something as effective as these on line examples and were really happy with the results.” Dr Francis says.

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Updated:  11 December 2013/ Responsible Officer:  Director, RSPE/ Page Contact:  Physics Webmaster