End of Year Lab Design Projects

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.

1. 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.
2. 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.
3. 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.

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