There are many different types of glass; all are composed mainly of but the addition of...

There are many different types of glass; all are composed mainly of but the addition of other elements can change the color and other properties substantially. One type of glass, called Pyrex, incorporates small amounts of the element boron, which gives it a very small coefficient of thermal expansion. Most oven-safe dishes are made from Pyrex because it tends not to crack when heated or cooled. Explain why.