In the quasistatic adiabatic expansion of a gas, the entropy remains constant, although more volume in position space becomes available through the expansion. If the volume in position space increases, what must happen to the volume in momentum space and the temperature? In adiabatic demagnetization, if the magnetic moment of the spin system decreases as the external field is removed, what happens to the spin entropy of the system, the entropy in the kinetic and other degrees of freedom, and the temperature?