The evaporation lab is a product of Ken Forbus Qualitative Reasoning Group here at Northwestern. Their home page is a good place to look for general information and documentation.
You can run the evaporation lab directly from the Web; a users manual is also available. The teachers manual includes a section on suggested activites. Use those as a guide to exploring the lab, potentially answering the questions posed in the manual or considering an activity of your own.
If youre interested in further reading, there are a number of papers listed on the web site. One that I have a hard-copy of that doesnt seem to be listed on the web site is "Self-explanatory simulators: making computer partners in the modeling process," and I can make a copy for those who would like one.