A Bar Breaker Cast Iron allows for the study of heat expansion and contraction, showcasing the significant amount of force involved in the process. It features a steel bar held in place by a cast iron frame and pin, while a gas burner located in the base heats the bar. As the bar expands, it applies pressure on the cast iron rod, eventually causing the cast iron pin to break with a distinct sound.

When the steel bar is heated, you can insert and secure another pin. Then, as the bar cools and shrinks, the cast iron bar will once again break with a noticeable sound. 

*includes a set of 10 small cast iron rods