Molecules

We tend to think of molecules as sub-microscopic little things, and most are. However, with a process known as cross-linking, some molecules are quite large. Cross-linking is used to make plastic, paint, and synthetic rubber stronger. In the same way you can separate pieces of gravel, yet separating a large boulder is much more difficult, cross-linked materials resist separation.

If you are old enough, you may remember when most plastic items were fragile. If you dropped a camera or remote control on the floor, it would shatter. Modern plastics are usually cross-linked so shattering is much less common.

Now, your phone’s casing is made from a single cross-linked molecule. The rubber part of the tires on your car are one molecule each. In fact, the paint on your car is one giant molecule.

The picture above shows that a board was pushed right through a tire in the Alaska earthquake of 1964. The point, however, is that all the rubber of a modern tire is a single molecule. This is an old tire from before cross-linking technology. You can see the extent to which the rubber is coming apart. The paint on your car is also a single molecule.