Sam Belflower, age 9, of Pamplico, South Carolina, for his question:

Why is it useful to make all these plastics?

Ages ago, people made their pots and pans from molded clay and dried them in the sun. Earthenware dishes made of over baked clay are really plastics. Our ancestors made them before the dawn of history so the idea of plastic materials is not new. Thousands of years ago, people had seething hot furnaces to make glass. And glass is a plastic. But we did not start making plastics on a grand scale until modern times. There are reasons why we have to make them. There also are reasons why we had to wait.

In olden times, people found in the ground all their metals and clays and building stone. They had plenty of time to make these natural materials into the things they needed. They patiently wove their cloth from sheep wool and plant fibers. Nowadays, there are more of us. The earth's natural supplies are running short. We need to replace the olden materials with cheaper, easier to handle, man made materials. And just at the right time, our clever chemists discovered how to create all those useful man made plastics that keep on improving our everyday lives.