When tempered glass breaks it blows into a million tiny pieces. While startling this actually makes the glass safer when it breaks as there are no large, heavy pieces which are actually more likely to harm.

I never understood why otherwise strong tempered glass would break so spectacularly but this article and the videos below of “Prince Rupert’s Drops” (small drops of tempered glass) show how the inherent tension caused by quick cooling makes glass stronger, but explosive.

via MAKE