I’ve been thinking of updating my Standard Temperature and Pressure Calculator: http://www.1728.com/stp.htm For one thing, I don’t know how prevalent pressure measured in torr is.
I’ve been thinking of adding drop-down menus for choosing units (4 for temperature, 8 for volume and 12 for pressure).
I know that STP is 0°Celsius and 101325 Pascal.
For ease of use, I was wondering what the default values should be for volume, temperature and pressure. According to the Systeme Internatiole, http://physics.nist.gov/Pubs/SP811/sec04.html the values would be
cubic meter, °Kelvin and Pascal (respectively).
However, in reality I don’t think laboratories measure values in cubic meters or
°Kelvin. So, for people using this calculator for real lab work (or even schoolwork) would default values of liters, °Celsius and Pascal be the best choice?
In work with gas dynamics, I’ve seen Kelvins used more often than degrees Celsius and kiloPascals (kPa) used most often for pressure. If it were me, I’d default to liters, Kelvins and kPa.
Thanks for the quick answer QED
Incidentally, I didn’t see you in the “US Intention To Convert To Metric” thread.
It seems the kind of thread you’d like.
Incidentally, I previewed my posting and everything looked fine - but I obviously did NOT check the title - SYANDARD - geez - where’s the “smack the head” icon???
When I measure pressure qua pressure, it’s in mm Hg (torr). However, for various purposes I express pressures as atmospheres, bar, inches Hg, and occasionally inches of water.
nametag
Thanks for the info.
That’s the reason that the calculator will be undergoing an update with a great many choices for volume, temperature and pressure units.
wolf_meister, anyone who’s studied the relevant documents should know that there’s no such think as a degree Kelvin. Temperature is not measured in degrees in the SI unless you are working on the Celsius scale: It is measured in Kelvins.
Kelvin is the SI unit for temperature. Most labs don’t use Kelvin. (Exceptions include NIST, primary standard labs, and anyone doing thermodynamic work.) It’s been my experience that most metrology and research labs use Celsius, and most testing labs use Fahrenheit.
CrafterMan’s comment about who uses what is right on in my experience, but you can learn more by looking at why. Places that just record data often use Celsius because it’s convenient and most people who use it have an internal reference. Places that use data usually use Kelvin because when you’re plugging temperatures into formulae, that’s what you typically need. So a weather station might record Celsius because it’s just tabulating data, but a lab which is taking measurements from which it will calculate other values (e.g. surface temps to calculate heat transfer) is going to measure Kelvin (in my experience). That suggests that Kelvin would be the best default for your calculator because anyone using the calculator is actually using their data, not just recording it.
FWIW, in my fluid dynamics lab we used kPa and Kelvin. I also used torr and degF for some things because we had some ancient equipment that could not be upgraded, but when taking measurements, it was kPa and Kelvin. But it really depends on your field - in gas dynamics, they typically use Pascals because they’re dealing with low pressure and the numbers are sane.
Well, I believe I have it ready for viewing. The “new and improved” calculator is at: http://www.1728.com/stp2.htm
And it has a link to the old calculator. Crafter_Man
As for my primary audience, that’s a good question. I run my website just as a hobby. I’d say the STP calculator gets about 1,500 hits per month. However, it is very rare that I’ll get any E-Mail of thanks or suggestions. So, as for people using that particular calculator - it could be someone in a cutting edge plasma technology lab OR it could be a kid taking high school chemistry.
Why not include a “Feedback” link prominently displayed on each calculator along mwith a little message like “If you found this calculator useful or have comments or suggestions, click HERE.”? On the page that takes them to, have a little survey or something along with the comments textarea.