A crude version of the material we know as glass was most likely first produced about 4,500 years ago. Around 1500 b.c., artisans learned how to press glass in open molds, producing a variety of shapes and containers. The process, however, was slow, labor intensive, and expensive. Pressed glass was considered as valuable as precious metals. More than a thousand years passed before people discovered how to shape intricate and delicate objects through glass-blowing techniques.
Today there are a variety of glasses.
These materials have ingredients and structures that produce distinct characteristics. If the glass layers shatter, the pieces don't go flying off. Instead, they are held together by the plastic. Laboratory glassware contains a large amount of silica and boric oxide. These components produce a material that can withstand sudden temperature changes.