Dr. John Selker will talk about the physics and chemistry of clay. Come delve into the microscopic crystalline world of alumina-silica hydrate, learn why clay is plastic, why it shrinks, why it cracks, why it deforms, why and how it vitrifies, why it is such a unique and marvelous substance!

John is a professor of hydrology and teaches classes in soil science. He is an expert on how water moves through soil – or in the case of certain clays, doesn’t move through it because of its crystal structure.