Hello. I am currently investigating the relationship between the thickness of insulation and the temperature of the system being insulated. The material I used was card - not a common insulator, I know, but the variable in question was thickness. What I found was most interesting: for the first 7 minutes or so of testing, using two sheets of card appeared to cause the system to heat slower than just one sheet of card, as expected. After 7 minutes, however, the two seemed to behave exactly the same until around the 20 minute mark. Another curiosity can be seen between the data from 5 sheets of card and 3 sheets - after 30 minutes, the temperatures of their respective systems appeared to be almost exactly the same. I am currently attempting to theoretically explain my results - does anyone here have any ideas? I have included the graph's spreadsheet as an attachment to the thread. Thank you!