David MacDonald, age 10, of  St. Catharines, Ont., Canada, for his question:

WHO INVENTED THE SUBMARINES?

A Dutch scientist named Cornelius van Drebbel came up with the first workable submarine in 1620. It was a wooden rowboat that was covered with waterproof hides. Then, during the century that followed, many other undersea craft were designed and constructed in various parts of Europe.

During the Revolutionary War, a student at Yale College named David Bushnell designed a one man submarine powered by a hand cranked propeller. He called the craft the Turtle. In 1776 the Turtle made an attempt to sink a British warship in New York Harbor but it failed. This was the first known attack by a submarine.

In 1800 American inventor Robert Fulton built a copper covered submarine called the Nautilus.