Carolin Skoro, age 12, of Gary, Indiana, for her question:

Now does the ocean depth compare with the height of the land?

We measure the ups and downs on the surface of the earth from the average level of the world ocean. Standard sea level is the mid way point between high tides and low tides, and it is a very tricky marker to estimate. The height of a mountain is measured in feet above sea level. The highest peak is Mount Everest in the Himalayas of Asia. It is estimated to be 29,028 feet above sea level. The depth of the ocean floor is measured in feet below sea level. Charting the ocean floor is rather new and far from finished, but already several deep ditches have been found down there. The deepest so far found is Challenger Depth, southwest of the island of Guam in the Pacific Ocean. It is 36,198 feet below sea level. If Mount Everest stood in this hole, its snowy crown would be 7,170 feet or more than a mile below the waves.

On a global picture, the average height of the bumpy land is estimated to be 2,757 feet, a little more than half a mile, above sea level. The average depth of the world oceans is estimated to be 12, 450 feet a little less than 2 1/2 miles below sea level.