A teacher’s guide to using foam models to demonstrate principles of different kinds of faults. This guide is a minor modification of the original teacher’s guide developed by Professor Larry Braile of Purdue University. Three-dimensional visualization is sometimes challenging for students. Use of three-dimensional foam models to represent blocks of Earth’s crust can allow students to visualize how crustal blocks across different types of faults. It is important to emphasize that blocks of crust often move in “jerks” rather than sliding smoothly and steadily. Earthquakes are the result of sudden motion of blocks of crust along a fault. Students sometimes find the expression “earthquakes are jerks” memorable and a key to understanding the connection between faults and earthquakes.