Snakey oscillations?

Our Physics technician, Simon, produced this video during his hols.

Apparently it took an absolute age and the patience of a saint to get to this standard, but what a resource?! As soon as a I saw it, my mind started buzzing with ways I might use it in the classroom.

To prompt questioning

In the first instance, I think it’s sufficiently intriguing to catch a student’s eye and suspect they’d watch it more than once. I’d also contend it would prompt questions and leave them thinking “Why is it doing that?” or “How was that done?” So the first thing I’d probably do is to ask them what questions do you have? (If you’ve not seen 101 Questions by Dan Meyer, it’s well worth checking out and if this video hadn’t been just over the 1 minute limit, I’d certainly have posted it there). If you’re simply using it as a lesson starter, that might be as far as you get, but there’s clearly potential for more.

To encourage close observation

There’s scope here for students of all ages and capabilties to participate at their own level. Precisely how detailed do observations need to be to capture the complexity of the motion. Maybe observations could be crowd-sourced from the class, either using good old paper sticky notes, or an electronic version like Padlet. The notes might then be arranged in different ways: a timeline of events, thematically etc. Could the students then describe what they saw in sufficient detail for someone who hadn’t seen the video to be able to picture the event?

Hypothesising

Given the questions they’ve already asked and the observations they’ve made, are they better placed to offer hypotheses which begin to explain what they’re seeing? What is causing the effects? Then of course, how might they test their hypotheses?

Taking measurements

What measurement might they want to take to try to make sense of what is happening? And how would they do that from a video which is on screen. These are clearly the kinds of practical skills upon which students are assessed, but rather than the traditional pendulum experiment where we might provide them with the instructions how to set things up, what measurements to take and how to take them, here’s a real phenomenon, based on the same theory, but which challenges them to come up with a novel method for taking the measurements … and in attempting to ensure accuracy, what problems do they face? Of course that can be followed by displaying and/or processing the results in whatever way is deemed appropriate.

Replicating

So having interrogated the phenomenon in the detail they now have, how would they set up their own version? Or a better or different one? There’s now the option to delve into the practical aspects in much more detail, but be warned, Simon assured me that the adjustments that were needed to the length of the pendulums to produce such subtle changes in periods of oscillation were incredibly fine, which is where the patience came in. Perhaps with older students there’s an alternative approach? With measurements of the difference in time periods between different golf balls, by using the equation for a simple pendulum, can they establish what the difference in lengths must be? Maybe then they might be able to set up their pendulum snake from theory alone? Those interested in coding or with sufficient design skills might be able to produce an animated representation.

Maybe the effort and time Simon put in could be repaid several-fold?