Jack Shay, aged 14, of Salt Lake City, Utah for his question:

What is safety glass made of?

A broken window pane splinters into fragments. These gagged splinters are hard to see. You know how dangerous it is to pick up shattered glass. Naturally you wear thick gloves and use a brush for that kind of fob. Also watch where you put your feet. For a splinter of glass may pierce a shoe.

This kind of glass caused much danger in traffic accidents. So safety glass was invented. The idea was to make  windows of glass that refused to shatter and scatter in all directions. Nothing can stop brittle glass from breaking into splinters when hit. So the plan was to keep the splinters from flying in all directions.

Safety glass is made of three layers. A thin layer of transparant plastic is sandwiched in between tyro layers of plate glass. The material used is so fine that the safety glass is clear as a window pane. But it does not scatter its fragments like a window pane. The layer of plastic holds the splinters together, for a time at least. When broken, safety glass looks like frost on a window pane. Hut the white pattern is really made of splintered glass held together by a layer of plastic.