Gregory Brown, age 12, of Wichita, Kansas, for his question:

Flow much of the earth's surface is above water?

On a globe or a map of the world, the earth seems to be a very watery planet. And so it is.  If we divide the surface of the earth into one hundred equal parts, only twenty nine of these parts are high enough to poke up above the water. The great oceans and their various gulfs and seas cover an area of some 140,500,000 square miles.

On an average, the seas are between two and a half and two and a quarter miles deep. If all this water could be frozen solids it could make a ball more than one third as large as the moon. If the surface of the earth were all even, with no ups and downs, the oceans would cover everything with water one mile deep. There is, however, no fear of this. For the 29 per cent of the earth's dry land is well above sea level and the mighty oceans rest in deep basins. They may slop over coastal areas, but sooner or later they must retreat.