Copper has been the mainstay of plumbing supply systems for decades. While the system is very popular it is particularly susceptible to freezing.
Copper plumbing is rigid and does not stretch when ice forms. Water expands approximately 9% when it freezes.
Plastic plumbing systems have some stretch to them and are slightly more freeze resistant. Modern PEX plumbing, in particular, seems to be able to take some freezing without bursting like traditional rigid copper plumbing.
In this video demonstration, you will be able to see how various types of plastic plumbing and copper behave when sections are frozen. The plastic did amazingly well. I was resistant to the idea of PEX Plumbing in the past but no more. Seeing this video has only confirmed to my mind that this is a very reliable and economical way to supply water to your home. I now have a lot of it installed as we swap out the old galvanized plumbing in my house.