Re: [Phys-l] picket fence free fall vs. ticker tape timer

[John Gastineau <jgastineau@vernier.com>]

On Sep 16, 2007, at 1:54 PM, Rauber, Joel wrote:
> The Physics Teacher, Vol. 35, April 1997.
>
> Vernier changed their coding of the data taking as a result of this
> article, as I understand it.
> ________________________
> Joel Rauber
> Department of Physics - SDSU

While the algorithm used for photogate motion timing (aka picket  
fence timing) used by various Vernier programs has been changed over  
the years to make more raw data available, our software never made  
the gross error described in the excellent paper above (which does  
not mention Vernier).

The paper describes data from a picket fence free-fall experiment as  
analyzed by a commercial software package from another interface  
company, and how the software's developers make an error that creates  
poor results from good raw data.

The full title is "Dangers of Automated Data Analysis" by William J.  
Leonard. TPT volume 35, April 1997, page 220-222. It's well worth  
reading, and is within reach of better introductory physics students.

--
John Gastineau
Staff Scientist and Partner
Vernier Software & Technology
jgastineau@vernier.com