Mary Ann Hughes, age 13, of Hukimer, New York, for her question:

What causes a quicksand?

Right now, Mother Nature puts on her lavish spring show to tempt us outdoors: Beauteous buds are bursting, birds are singing and the fresh mild air is a buzz with busy insects. Everything is new and lightly perfumed with spring flowers. But let's remember that there is another side to old Mother Nature. Her wondrous world also is beset by a selection of sneaky booby traps, just waiting to do us in.
In the world of nature, and everywhere else, it's always a good idea to watch out for the worst. Knowing about hidden perils should not detract from our enjoyment. Far from it. For example, last summer a number of people were trapped by quicksands and quagmires, soupy swamps and soggy bogs. Many of these incidents happened because the people did not understand these sneaky hazards.
So, before we set forth to explore the summery outdoors, let's prepare ourselves to outsmart the possible mishaps. For example, let's learn to identify the poisonous snakes likely to be lurking in our neighborhoods and promise ourselves to run, not walk, in the opposite direction. Let's practice swimming    in case we fall in. Let's chart our trips on a detailed map    in case we get lost. Let's renounce cave exploring    unless accompanied by a qualified spelunker.
And let's watch out for quicksands, swamps and other soggy booby traps. Strictly speaking, quicksands occur on ocean beaches and along the brinks of lakes and rivers. They are pockets of sand or fine silt mixed with water. Bogs and swampy quagmires are mixtures of water and thick soupy mud. They form in flood lands and in the basins of partly dried up lakes. In all the cases, the soggy mixture is too thin to walk upon and too thick for swimming, though a person is sure to float on quicksand and so won't drown in it unless he panics.
These soupy pockets form where hollows in the underlying bedrock form solid basins. The solid rocky basins capture and hold water from rivers, from lakes or from the sea. Sooner or later water becomes mixed with sand or mud or decaying vegetation. If you step into it, you sink down. And the solid floor of the basin may be a few feet or perhaps 30 feet below the surface.
Usually these booby traps are disguised to fool the eye. A quicksand on an ocean beach may look like a safe stretch of sand. A quicksand by a lake or river may look like a safe stretch of flat, wet, silty mud. Often the surface of a boggy swamp is overgrown with a surface layer of healthy looking weeds.
Our best defense is to learn all we can about where these pitfalls are    before we venture into unexplored territory. Rangers in the area have this information. Some spots are marked on maps and many others have posted warning signs.
Getting trapped in one of these soupy pockets is terrifying and can be very dangerous if you lose your head. A sensible explorer never goes exploring alone. A rescue of this sort calls for expert help someone is needed to go for assistance. Meantime, the victim is advisee: to stay calm and try to avoid struggling    which only makes things worse.