Re: [Phys-L] problems with the teaching of algebra

["Marc \"Zeke\" Kossover" <zeke_kossover@yahoo.com>]

I worked in a material science lab that did a lot of hard vacuum work. We used five different units for pressure.

1. PSI (pounds per square inch): compressed air bottles regulators
2. Pascals (N/m^2): computer software
3. Torr: vacuum gauges, usually 10^-8 or 10^-9 torr
4. Atmospheres: engineering journal articles about final pressures for hydrogen storage
5. Bar: older vacuum gauge on a piece of equipment that was too useful to stop using

Made me appreciate SI all the more.

Zeke Kossover



> ________________________________
> From: "rjensen@ualberta.ca" <rjensen@ualberta.ca>
> To: Phys-L@Phys-L.org 
> Sent: Wednesday, October 15, 2014 1:02 PM
> Subject: Re: [Phys-L] problems with the teaching of algebra
>
>
> The SI unit of pressure is the pascal -- not commonly used.
>
> The metric near-equivalent of atmospheres is the bar.
> 1 bar = 10^5 Pa = 100 kPa
>
> ISO and IUPAC changed the standard state from 1 atm to 1 bar in 1982.
> The only chemistry textbook I have seen that uses bar in is mine; all
> the rest still use atmospheres.
>
> Dr. Roy Jensen
> (==========)-----------------------------------------¤
> Lecturer, Chemistry
> E5-33F, University of Alberta
> 780.248.1808
>
>
>
>
>
> On Wed, 15 Oct 2014 19:01:57 +0000, you wrote:
>
> > As another wrinkle, we often teach students that it is "best" to always use "standard" units.  Eg if you measure in m, kg, and s, your answers will come out in N, J, & W.  So if you want your later calculations to come out in "appropriate" units, measuring in meters is most "appropriate"! 
> >
> > > -> > 2. Which of the following units would be most appropriate for 
> > > -> > measuring the length of a pen?
> > > -> > A: Miles
> > > -> > B: Meters
> > > -> > C: Micrometers
> > > -> > D: Centimeters
> >
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