Re: [Phys-l] formatting uncertainties

[Michael Porter <listmoe@gmail.com>]

On Jan 23, 2008, at 12:38 PM, John Denker wrote:

> IMHO one rule should be don't round off unless you are sure it
> is safe.  And the typical HS student will rarely have a good
> feel for what is safe and what is not.

>  ... and there should never be a penalty for keeping
> more than N digits.

There *is* a penalty -- Some students (thankfully, not many) write  
down every single digit that appears on their calculators, every time  
they write an intermediate or final answer, to the tune of dozens of  
times per exam. If the answer is precise to three digits and they are  
writing ten, then that is comparable to writing their phone number  
(or any random string of digits) next to each of these values. I ask  
them if that would constitute good use of their time, and they  
generally agree that it is not. They'd rather use that time to  
complete questions, check answers, etc.

Mike

---
Michael Porter
Colonel By Secondary School
Ottawa, Ontario, Canada