Glenn Johnson, age 10, of Okemos, Michigan, for his question:

What makes a tidal wave?

Twice every calendar day, the ocean tides wash up and down the beaches. But these are the normal waves of the tides. Once in a while, stupendous waves rush in from the sea and douse the land with monstrous waves like raging mountains of water. Some people call them tidal waves. But because these disastrous monsters are so different from the waves of the ordinary daily tides, perhaps they should have another name. A lot of people call them tsunamis.

Several different events may cause a mighty tsunami. After all, the oceans are great basins of water    and water tends to heave and slop around. The ocean waves are whipped up and driven by the winds. Gale winds and hurricanes pile up great mountains of water. Often they hurl this heaving water at the shore. It bashes inland in a tsunami type tidal wave. Earthquakes and volcanoes sometimes happen in the bed of the sea. This upsets the water in the vast ocean basins. It heaves up in enormous waves and travels maybe a thousand miles. When it reaches a shore, it sends a tsunami smashing over the land.