Mike Levine, age 9, of Sioux City, Iowa, for his question:

Why don't whirlpools form in lakes and seas?

It is true that most whirlpools are in fast flowing rivers. But the wildest ones form in the sea and sometimes smallish whirlpools form in a lake. All of them form when something forces a lot of water to turn and swirl around a spiraling circle. The something may be a mass of stubborn rocks, the wind or the mighty tides of the oceans. A swift river is a strong, streaming current. When rocks stand in its path, they force the current to sweep around in swirling whirlpools.

Along the coast of Norway is a monstrous whirlpool called the Maelstrom, It forms when the mighty ocean tides are trapped and turned by massive rocks. Lake waters tend to be calmer than swift rivers and tidal oceans. But sometimes a gale wind whips up waves and drives a lake over its shores. If stubborn rocks stand in the way, they may force the wind blown current to turn and swirl around in a whirlpool.