Kilnforming glass can yield results that range from elegantly simple to intriguingly complex. But when a piece emerges from the kiln cracked or broken, the results are just disappointing. The good news is that a piece always breaks for a reason. Understanding the working properties of the material can keep it from happening. This lesson covers two of the most common causes of a piece breaking: thermal shock and improper annealing. You will learn what thermal shock is and how to avoid it, the consequences of poor annealing and ways to anneal successfully, and considerations for designing firing schedules for a variety of different types of pieces.