Hey guys! Was wondering if someone could help me out. I'm doing a thermodynamics topic and have an issue explaining the following : I conducted and experimental procedure involving a boiler apparatus. (Similar to this one >> http://www.armfield.co.uk/th3_datasheet.html" [Broken]) Now the idea was to find the pressure and temperature for a set of data points. These data points are then to be compared to the "Steam Table" data points. http://www.uploadpad.com/files/dfsdfsdf4.jpg [Broken] The red line is the experimental results and the blue is the data gained from the steam tables. There is roughly a 4 degree Celsius difference at each pressure point. I have to explain why there is a variance in my results? Now human error or apparatus error is just not good enough for the explanation. Is there a concrete thermodynamical explanation? Help would be greatly appreciated! Ohh on the side note: How can I improve the experimental apparatus or conditions to get closer to the steam table results??