Mary Lee Jorgensen, age 15, of Lemon Grove, Calif., for her question:

How deep is the Arctic Ocean?

The Arctic is the smallest of the world's oceans. The Atlantic could swallow it up five times and still have room to spare. The vast Pacific could swallow the Arctic Ocean a dozen times. And the Pacific, our biggest ocean, is also the deepest.

The Arctic, our smallest ocean, is the shallowest. Its average depth is 3,953 feet, less than one mile. The average depth of the Pacific is 14,048 feet, almost three miles. The average depth of the Atlantic is more than 1,880 feet, over two miles.

The small, shallow Arctic Ocean, however, has some features all its own, It is the world’s coldest ocean. For almost a mile below its icy waters is the North Pole.