Storytime with Thursday Next (Jasper Fforde), and her Uncle Mycroft's entropy-detecting entroposcope. Why are large-scale systems capable of producing irreversible processes (like glass breaking, or red and blue Kool-aid mixing), even though the microscopic processes are reversible? We finish the electronic heat capacity of metals, first with an easy estimate to see that C~T, then with the full calculation. Using ideal gas processes (isothermal expansion, isentropic expansion), we build a Carnot engine and discuss its efficiency. You can't beat Sadi Carnot. Class Exercise: calculate the work done in one cycle. Class discussions: the chemical potential has a slight temperature dependence in three dimensions, but not in two. Why you should never hook lead pipes to aluminum pipes in your house. A little bit about melting. Can you convert heat entirely into work, or work entirely into heat? Lecture Audio