Mr. Meyers,

Please check your code. Did you actually have

"Temperature">Quantity

Also, there is an example in the documentation of the function AirTemperatureData:

Grid[SortBy[{#, 
     ThermodynamicData["Air", 
      "SoundSpeed", {"Temperature" -> AirTemperatureData[#], 
       "Pressure" -> AirPressureData[#]}]} & /@ 
   CityData[{Large, "Colorado", "UnitedStates"}], Last], Frame -> All]

It gives:

This suggests that there is a real problem.

M.

Gentlemen,

Thank you for pointing out this problem. I filed a report for developers.

p.s. If 10.0 customers find problems with other *Data functions, please start new threads.

I thought it might be that Mathematica was missing the phase transition, but problem seems to be across entire (p,T) domain.

Compare output of ThermodynamicData with Diagram of the speed of sound of Water and Steam

c[p_, t_] :=  ThermodynamicData["Water",   "SoundSpeed", {"Pressure" -> Quantity[p, "Bar"],  "Temperature" -> Quantity[t, "DegreeCelsius"]}]; ContourPlot[Evaluate[c[p, t]][[1]], {t, 0, 800}, {p, 0, 1000},  Contours -> 30, Frame -> True,  FrameLabel -> {"T [\[Degree]C]", "P [bar]"},  PlotLabel -> "Sound Speed in Water [m/s]\[NewLine](ThermodynamicData, Mathematica 10.0)", PlotLegends -> Automatic, ColorFunction -> (ColorData["TemperatureMap"])]

Mr. Carlson,

About updating:
The data paclet servers will be updated. In the "old days" I would have recommended looking in the directories given by

$BaseDirectory

and

$UserBaseDirectory

for Paclet directories, and deleting them.

It appears that now the easy way to get data updates is to make sure the "Automatically check for data updates" line is checked in Preferences - Automatic Updates - Data Updates. (Experts feel free to correct me.)

As the Technical Engineer promised, we were able to correct this in our latest push to production. Which was this afternoon. This will resolve all of the incorrect SoundSpeed results. The documentation errors I'm told should be resolved in the next documentation update which is planned in the next week or so.

Sorry for the inconvenience and thank you for bringing this to our attention.

Its possible this result may be cached from earlier in your session (we do some saving of results from ThermodynamicData to speed up large repetitive calculations). I would try rerunning the calculation in a fresh session or kernel. You should see the correct results then.

Okay, I restarted the kernel and now it looks better apart from this message:

GeoPosition::invdtm: Unknown geodetic datum ___. Use GeodesyData["Datum"] for a list of available named datums. >>

Best wishes, Marco

Marco,

Thank you for the reminder. This warning was in the ref/AirTemperatureData, Neat Examples, example since 10.0.0 was released.

A formal report to developers has been filed. An odd warning message does not have the Yipes! value that incorrect results do, so it might not be corrected as quickly.

Bruce

Glenn, how long did it take of this plot to run on your machine? Mine's been working on it for over 10 minutes. I'm on OS X 10.7.5

I've been writing a package that calculates steam properties according to IAPWS-97 methodology. I expect I will continue with this work.