Rick Bebee, age 13, of Garber, Oklahoma, for his question:

Where do the waters of the Great Lakes originate?

On a map, the Great Lakes look like a big blue brooch pinned on the heart of North America. Their surface waters cover an area of 94,650 square miles and together they form the world's largest body of fresh water. Their waters cone from the land around and below them and then drain on down to the Saint Lawrence River, out into the north Atlantic Ocean. You would expect that several great rivers would be needed to feed them, but no such large rivers appear on the map.

However, a detailed map shows a great many smallish rivers; plus countless little streams and creeks flowing into the lakes: They trickle from the surrounding land, draining rain water and melted snows. And lots of little streams can carry as much water as one great river. There are also springs in the area, some of them in the floors of the lakes. They help the numerous streams to keep the Great Lakes plenteously filled.