Inga Bowie, age 8, of Houston, Texas, for her question:

How are islands made?

The earth has many recipes for making islands. Some poke up from below the water. Some are left high and dry when water flood in around the land. Almost every island has a different story to tell about how it was born. It may be very large and very old. Or it may be small and still waiting for its first birthday. But whatever its story, every island is a piece of dry land with water around it on all sides.

The floor of the ocean under the water is as solid as the dry land. It also has mountains and valleys. Sometimes the peaks of underwater mountains poke above the waves. They form a chain of islands. Volcanos also erupt on the sea floor. Sometimes they pile up cones high enough to form islands of dry land. If you trace back millions of years, you find that the land and the sea often changed places. When the water flooded the land, it often left the tops of hilly islands. And some islands are built up patiently by tiny corals and other sea creatures.