Thermodynamics and Time

Learning Goals

This section is some "light reading" that puts some of the concepts of this chapter in a practical and a philosophical light.


Because the "real" universe has no surroundings, the universe is an isolated system. In an isolated system there is no energy change to act as a driving force for the system to proceed. Therefore the driving force for the operation of this entire system (all the planets, stars, everything) must be increasing entropy. It is this increasing of entropy that gives a time direction to our universe and hence the philosophers will sometimes talk of entropy as being "time's arrow". We must remember that this conclusion is for the entire "system" and not individual subsets of systems such as our planet, or our galaxy. Entropy can be decreasing as time increases in many of the subsets of the universe.

Web Activity

  1. Do a web search of "entropy time" and report some of your findings on the bulletin board of WebCT.
  2. Here is a site to further elaborate on some entropy concepts: more entropy


    Web Author: Dr. Leon L. Combs
    Copyright 2000 by Dr. Leon L. Combs - ALL RIGHTS RESERVED