Sharon Burris, age 12, of Bloodale, Cal, for her question:
How does quicksand form?
A stretch of golden beach always looks inviting. It beckons us to run on bare feet to build castles and dig moats. However, it is wise to test a newly discovered beach before trusting it too far. There may be times when it turns into a tricky quicksand.
The tricky old quicksand often plays a role in hair‑raising tales of adventure. Maybe our hero, running from a bad man, gets caught in such a booby trap. He steps onto what looks like solid ground, only to find himself in a hopeless bog. His feet sink down and he cannot lift them. A sucking from below pulls him down and down until he is almost swallowed up. Help, of course, arrives in the nick of time. A rope is thrown to him and he is dragged to safety.
This is the story book version of quicksand. Actually, a real quicksand is very rare. It is a mixture of sand and watery too thick to swim in and too thin to support your weight. It occurs where a layer of sand rests on a layer of solid rock. When this pattern occurs below tide level it forms a trap for tidal waters.
You can see how this happens from playing with sand and water. Make a soupy mixture of sand and water in a pail. The water sinks through the sand but cannot drain away through the pail. In a quicksand, the water is trapped like the water in the pail. It is slow to drain back to the sea. The tide pulls at this trapped water and a person caught feels he is being pulled down. Actually, the pull is from the water trying to drain home to the sea. This type of quicksand will drain dry and be safe between high tides.
A few quicksands remain soggy and dangerous all the time. These are sandy pockets resting in buried barriers of solid rock. These sands are flooded with every high tide and there is no way for the trapped water to drain away.
A bog is first cousin to a quicksand. It usually forms in the bed of an old lake. The water is choked with vegetation. Certain mosses like to live in the stagnant waters of an old lake, every generation a new layer of moss grows on top of the old. The stagnant water is a soupy mass of rotting plants with a brilliant green layer of new plant life on the surfaces.
It is very dangerous to step into a bog for the solid ground may be 30 feat below the surface. Naturally none of Andy's friends ever go exploring old lakes without a proper guide. And no sensible parson ever goes rushing onto a new beach without making sure it is not a quicksand.