Jeanne Pendleton, age 11, of Parowan, Utah, for her question:

How deep is the ice over the North Pole?

The North Pole is under the Arctic Ocean and ice does not form as readily on sea water as it does on land. Tides and ocean currents tend to break the forming ice into chunks and floating islands. Nevertheless for most of the year the North Pole is frosted with lumps of drifting ice called the Polar Ice Pack. Through the Arctic winter, this ice may become five feet thick. For a few months, this polar ice may be a solid sheet. But spring soon breaks it up into ragged floes separated by stretches of open water.

This ice is frozen sea water. Drifting here and there are great masses of frozen fresh water. These icebergs and floating ice fields break of from the glaciers of Greenland and northern Canadg. Sometimes these icy islands drift over the pole, but as a rule, the North Pole is topped with broken ice floes perhaps five feet thick.