For example, we will learn later in the course that the electrons in metals can have substantial motion (a tenth the speed of light) at absolute zero....

For example, we will learn later in the course that the electrons in metals can have substantial motion (a tenth the speed of light) at absolute zero. An important insight you will learn from this course is that entropy is a deeper and more important concept than temperature and it is through entropy"s dependence on the energy of a system that one can define a temperature (the relation is 1/T = S/E with some qualifications). This reduces to T for ideal gases but can be used in many problems for which there is no kinetic energy at all, e.g., a material consisting of interacting magnetic spins or a black hole. Can you explain Maxwell"s demon?