When we think of glass as being very fragile, it is actually quite a strong material, especially under compression. It is extremely resistant to chemical attack, and is thus an ideal medium for storing foodstuffs as well as extremely corrosive substnaces such as sulfuric and nitric acids. Most pure chemical substances used in scientific laboratories are shipped in glass. Almost all equipment used to contain chemicals in scientific laboratories is made of glass. We will finish by mentioning three special kinds of glass.
Modern windows show essentially no distortion.
Older window glass had to be rolled. They are used for applications such as insulation where again the properties of glass are important. Photochromic means that the colour changes in the presence of light, and the colour change reverses in the dark. Such glass is made by incorporating a little silver chloride into the glass. The silver and the chlorine atoms are held in place because of the rigidity of the glass.