Re: Calories, calories, & joules (was Re: Our 'humiliating'

[Jim Green <JMGreen@sisna.com>]

At 11:59 AM 9/14/97 -0800, John wrote:

> On Sun, 14 Sep 1997, Jim Green wrote:
>
> > why would one use the unit "calorie" in a physics class.  
>
> Perhaps one wants quickly and approximately to specify the amount of heat
> that must be "done" to raise the temperature of a gram of water by a
> kelvin?  

Well, John, I applaud your usage!  And if you are willing to say this, you
can use any unit you wish w/o comment from me. (:-)

> Seriously, I don't see any good reason why we should deny ourselves the
> use of units--especially those that are based on meaningful and convenient
> standards like the calorie--just because they are not members of the SI
> system. If we are doing it simply to protect students from the need to
> perform complicated unit conversions, I think we are doing them a grave
> disservice.

Yes again, if you are teaching an intro class to full of pre-med types or
nurses, then I agree that the tide is just tooo strong to try to convert
them to the SI system at this time. (After all, nurses still try to
pronounce centimeters in two languages: centi in French and meters in
english -- Woe unto you if you try to correct THAT.!)

But in a HS physics class or a college physics class for physicists,
chemists, and/or engineers, I think it a disservice to use calories no
matter how convenient or entertaining -- "because it is the way we have
always said it". As you allude above there are too many things we do because
"it is the way we have always done it".  At some point we WILL be using the
SI -- Don't we have some modicum of obligation to proselyte it?  For
example, it is not too painful to refer to room temperature in oC (or even
K) is it? 





Jim Green
JMGreen@sisna.com