In my statistical physics class the partition function Z is used in the calculation of probabilities, and I even have a formula for it: Z=[itex]\sum[/itex]e-E/kT. While this is all very good I am having some trouble actually grasping what it is, qualitatively speaking. Would someone please be able to explain it to me? I've tried google-ing, and firstly it pointed me to this site, but I've also followed a couple of other links that don't make much sense to me... Cheers.