Reading a Psychrometric Chart
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This Demonstration shows how to read a psychrometric chart (also known as 
a humidity chart). Select the dry bulb temperature (x axis) and the relative 
humidity (green curves) using sliders. You can then check the box for 
"enthalpy" (blue lines), "specific volume" (red lines), or "temperatures" 
(gray arrows). When the "temperatures" box is selected, mouse over each of 
the three arrows to see the dry-bulb, wet-bulb, and dew-point temperatures. 
All temperatures are read on the x axis. Unchecking "relative humidity" does 
not remove the relative-humidity lines, just the labels. Select "display values" 
to see a table of all the values obtained from the chart for the selected point.