Why does tempered glass shatter into tiny cubes instead of sharp shards?

Tempered glass shatters into tiny, blunt cubes because of the internal stress created during its manufacturing process^[2][5]. By rapidly cooling the outer surfaces of hot glass, the surface contracts faster than the center, locking the exterior into a state of high compression while the interior remains in tension^[1][6]. This balanced stress causes the glass to explode into granular chunks rather than sharp shards when the surface is breached^[5][6].

Unlike ordinary annealed glass, which breaks into dangerous, jagged pieces, tempered glass is a safety material used in shower doors and car side windows^[2][5][6]. Laminated glass differs by sandwiching a plastic film between sheets to hold fragments together upon impact, which is why it is used for windshields^[2][6].