Glass tempering is a process that strengthens glass by heating it to high temperatures and then rapidly cooling it. This method increases the glass's resistance to impact and thermal stress, making it safer and more durable for various applications, such as in windows, shower doors, and automotive glass. During tempering, the glass is heated to around 620°C (1,148°F) and then cooled quickly using air jets. This creates a compressive stress on the surface, which helps prevent the glass from breaking easily. If tempered glass does break, it shatters into small, blunt pieces, reducing the risk of injury.