Re: CBL/Motion Detectors

[jwise@cinenet.net (Joe Wise)]

I have been using the CBL's with no trouble with 9th graders in high school.
They are very excited about uploading the data to the computer etc.  All of
my labs this year have been done outdoors.  This has been fun for me too.

The major problem I have had is that the plugs are not in all the way.  You
will swear that they are, but they aren't.  Trust me.

My experience with the detectors has shown them to be very sensitive in
their measurement position etc.

> 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
Joe Wise
Director, Crossroads Science Institute
Crossroads School for Arts and Sciences
1714  Twenty-First Street
Santa Monica,   CA     90404
(310) 829-7391