ABSTRACT
This chapter explains biophysics content, except in the homework. It describes the exceedingly different approach a physicist may take when grappling with a new sort of problem or phenomenon. The biologist describes complicated behavior of an organism. The physicist proceeds to propose a simplified model that can explain certain features using a few parameters, perhaps, the volume and mass of the cow. The feebleness of the spherical model is, of course, that its one or two parameters explain almost nothing of importance or interest to the biologist or farmer. Biosystems are clearly dominated by very many particles, so entropy must be crucial. Even in systems of single particles, entropy can play a dominant role when the process is one that has multiple possible outcomes. The distance calculations in the previous problem might have been done after it was learned that a cell with some intracellular aqueous NaCl concentration might encounter an aqueous solution of a different NaCl concentration.
