This Rubens tube was made by one of my physics students for her final lab design project. Pretty awesome. Last year I had a group who made a pendulum wave. Kids come up with some pretty awesome things to investigate when given the chance.
My end of year assignment to the students goes like this; I stand at the front of the room, tell them to design and perform a lab on anything physics related, including topics we have or have not covered in class. Go.
I’ve learned a few things about this. Some students have a hard time figuring out what to do. In particular there are three major errors students make in the ‘find a question’ phase.
- They know something they want to use but not what to investigate. I often get groups who want to use their car, or a motorcycle, or some other piece of equipment, but then they don’t know what to actually measure. I council them to start with a physics concept to investigate and go from there, rather than the reverse.
- They go too big. I often have groups who want to investigate air resistance with parachutes or launch watermelons across the football field. I mention that the same investigation can probably be done under more controllable circumstances.
- They can’t narrow in. Students come to me wanting to ‘do something with energy conservation’ or ‘friction.’ I tell them to think of the scenarios we have studied in these cases to see if a lab idea pops out of it.
Despite these pitfalls, students come up with some awesome stuff. Highlights from this year, including projects from both honors and regular physics;
- Energy loss of Newton’s cradle using photo gates to track ‘launch’ velocity vs. time
- Hysteresis of rubber bands (this won the fictional ‘never saw that coming’ award; a very cool lab that showed that rubberbands don’t contract the same way that the stretch)
- An investigation into ‘good’ and ‘bad’ sounding chords using FFT’s to compare and contrast
- Coupled pendulums. They investigated the spacing of the pendulums as well as the masses, and even tried adding a third pendulum.
- Investigation of the procession of a bike wheel gyroscope as a function of both axle radius and wheel speed. What was really cool in this one was the clever way they devised to measure the wheel speed (see picture below).
- Damped harmonic motion; This group took 42 trials and did some intense data crunching using Mathematica. They also had a very interesting setup, due to figuring out mid-stream that they needed the height to be comprable to the desired amplitude.
I have a couple of things I will be working on for next year. First of all, I was disappointed overall that the students tended not to use graphical representations in presenting their data. Lots of groups presented charts of data which they then used to draw conclusions; many times I didn’t have time to properly take in their data in chart form before they had moved on. I hope that my stronger focus on modeling next year will aid that process, as well as adding explicit guidelines that require graphical data representation.
Also for next year I plan to focus more (in general over the course of the year, but also for these projects) on the iterative nature of science. I was personally reminded that doing science usually requires many refinements and repeats of data collection when I investigated standing waves on a helical spring. Again I hope that modeling will emphasize this. My honors classes really had that idea down, but the regular classes this year, partially due to a more stringent time restriction, tended to follow the ‘one and done’ approach.
Since implementing this project 4ish years ago I have been very pleased with the student products, and I hope that modeling, clearer expectations, and gained experience on my part will further improve the experience for my students.