For a science project that I am doing, I am testing different types of insulation in between the walls of cups and how well they keep the water warm or cool. I've done some research on insulation, but I can not find anything that breaks it down into easy terms. Could you please break down R value into easy terms and maybe, if you know, which type(s) of housing insulation would be best to put between the walls of a regular sized cup so that it is the most effective to keep the water cool or warm.