Ellen speck, age l3, of Charlotte, N.C., for her question:
What is the Coriolis effect?
Gaspard G. de Coriolis solved a single problem that answered dozens of different questions. He proved why the trade winds angle toward the equator and why cyclone winds blow in spirals. He shaved what makes bullets veer off target and whirlpools swirl in opposite directions north and south of the equator.
This phenomenon of nature is called the Coriolis effect or the Coriolis force. Andy goes along with those who call it the Coriolis drift because the word drift explains it best. When something drifts, it moves or veers frown one place to another. The Coriolis drift affects objects moving on or above the surface of the earth and forces them to drift or veer from their targets. Winds and waters, bullets and planes seem to curve to the right in the Northern Hemisphere and to the left in the southern Hemisphere.
In the l9th century a French mathematician named Gaspard G. de Coriolis (l792 l843) related these apparent drifts to the rotation of the earth. He figured out the phenomenon in precise detail and it is named in his honor. The earth, of course, rotates on its axis once every 24 hours. As it turns around it takes us with it as though we were riding on a merry go round.
Imagine yourself on a moving carousel while trying to play catch with someone on the ground. Your merry go round makes one turn every l0 seconds and like the earth it turns in a counterclockwise direction. Your friend on the ground aims and tosses the ball to you. But before it reaches you, the merry go round has whirled you out of range. The ball aimed at where you were reaches a target some six feet to the right of where you are.
As a plane zooms along its path through the air, the earth below it is rotating in a counterclockwise direction. Observed from the ground, the path of the plane seems to curve. North of the equator this drift is to the right and south of the equator it is toward the left. suppose a 60 mile a second rocket were aimed from the North Pole at New York City without allowing for the Coriolis drift some 55 minutes later it would land on some farm near Chicago. This drift must be figured when aiming long range artillery and planning the paths of planes, rockets and spacecraft.
The Coriolis drift also affects the winds and waves. The north and south txadc winds are bent to blow toward the equator from the northeast and the southeast. The earth rotates below eddying whirlpools and curves them in opposite directions north and south of the equator.
Certain coastal areas can blame the Coriolis drift for some of their misty fogs. Off California, the prevailing winds and the drift cause southwesterly ocean currents. The moving currents are replaced by cool water rising from several hundred feet below. In summer, warm moist winds blow in from the northwest Pacific. The cooled water chills the air and causes its moisture to condense in hazy fogs.