Duane McDonald, age 12, of Fairfield, Conn., for his question:

Where does the Niagara Falls water go?

The five Great Lakes are linked together and their fresh wagers finally empty into the salty sea. Lake Michigan slips into Lake Huron through a narrow neck. Lake Superior steps 22 feet down a run of rapids into Lake Huron and Lake Huron drops its waters eight feet into Lake Erie. Most of the water in Lake Erie plunges 326 feet over Niagara Falls and flows on its way into Lake Ontario.

Lake Ontario narrows to become the wide river Saint Lawrence and the beautiful river slides down, down to a rendezvous with the Atlantic. There the fresh water gathered by the lakes and spilled over Niagara Falls is emptied into the sea.