Monty Hopper, age 12, of, Visalia# Calif., for his question:

HOW DOES THE ZIPPER WORK?

Zipper is a trademark but the word is generally used today to mean all types of slide fasteners. Made of either metal or plastic, the gadget works by interlocking parallel rows of teeth on the open part of clothing. As a slide tab moves up, the teeth are joined and the opening is closed.

The clever fastener was invented by Whitcomb L. Judson of Chicago in 1893. In 1913 a man named Gideon Sundback invented a new type of slide fastener and also a machine to make it. Then in 1924 an overshoe company named its fastener Zipper.

It would be hard to get along without the slide fastener today. It's a sealing device, in many cases, that is much better than buttons and bows.