January 11, 2007 - Purdue University http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch8/index.php

January 8, 2008 - Worcester Polytechnic Institute::http://www.wpi.edu/Academics/Depts/Chemistry/Courses/General/concept2.html

REQUIRED READINGS:

http://www.physicalgeography.net/fundamentals/10t.html

http://www.physicalgeography.net/fundamentals/10v.htm