Zylak, age 11, of Willowick, Ohio, for her question:

How deep is  a quicksand?

This measuring job is for experts and no, absolutely no, amateurs need apply. In fact, few qualified geologists would apply for a job measuring the depth of a quicksand. We may call it a bog or a swamp, a marsh or a fen  but it is always a tricky piece of territory. It may be a soggy mixture of silty mud and water beside a lake or lazy river. It may be a pit of soupy sand and tidal water by the sea. The sneakiest of these booby traps is a bit of drowned land where the dregs of an old lake are clogged with a covering of tempting green vegetation. This and every other type of quicksand is too soupy to support your foot steps and too gooey for swimming.

Almost always, the surface of the trap blends in with the ground around. You cannot look ahead and see it in your path. Its sides may be steep or sloping. One step in the wrong direction may lead you from dry land to dreadful disaster. The soggy soup is trapped in a basin shaped formation of solid rock, which may be wide or narrow. Its solid floor may be only a foot or two below the surface but most quicksands are deeper, much deeper. Geologists say that the deepest go down 30 feet or even farther. A quicksand shallow enough for you to stand on the bottom with your head in the air is very rare indeed.