This is the first year that I have used CBL labs in my introductory physics
course. We are on our third week of them at this point, and have been
having a lot of trouble with the motion detectors. Due to schedule
constraints, I personally teach only the fifth of five sections of lab, and
all the rest of the week have TAs rushing frantically into my office saying
"(One or more) motion detector doesn't work......." to which I respond
"PushinthecordstightlybesuretheCBLhasn'tturnedoff......." but more often
than not, this is not the problem. They don't work well even for me.....
Could persons who have had more experience let me know if this is a common
difficulty--does performance improve with practice, is there a short (God
forbid!) lifetime for the equipment, what ought I to expect??
Margaret J. Clarke
College of St. Scholastica
Duluth Minnesota