All of the fussing over these data are precisely the reason I have stayed
away from 'automated' data acquisition and analysis in introductory labs.
While we can argue the fine points of averaging techniques, etc. here on the
list, ALL of this is totally opaque to students. For air resistance, I'll
stick with position versus time data, even if it has to be hand timed (our
experimental data for a 3 gr, 7cm diameter foam ball fits a v^2 dependence
quite well--certainly well enough to convey the main pedagogical thrust of
the designed experiment).
My first experience with motion detectors was at an Indiana AAPT meeting at
Indiana State where they had recently installed a computer assisted lab.
Each table had a Mac SI, various sensors, a full assortment of standard
experimental equipment, and analysis software. One experiment I try every
year is using a tilted air track to study accelerated motion and in part to
measure the acceleration due to gravity. This never works very well (the
technique requires a photo-gate to be triggered AS SOON AS the cart starts
to move down the incline and that is difficult to set up properly). I
thought that using a motion sensor, an air track, and a cart with a
reflector might be the answer. A couple of us set up the experiment, took
the data, and tried the analysis. What we got was GARBAGE. Ultimately we
recognized that we did have to average over longer time periods, but even
then the quality of the data was crap. Now maybe in the ensuing years the
hardware and software have improved (but I think the same rangers are in
current use), but my immediate reaction was that while a couple PhD
physicist might be able to make 'some' sense out of the data obtained, intro
students didn't have a chance. I use the computer extensively for data
analysis, but still am shy about using it to actually collect data (again at
the intro level).