Alan Muscio, age 11, of Santa Maria, California, for his question:

Are the clouds moved by the spinning of the earth?

It seems reasonable to suppose that the spinning earth creates a whirling draft, strong enough to move the airy atmosphere and its flocks of floating clouds. But, this simple idea does not explain the facts. Experts say that clouds are moved by the interaction of.several complicated forces.

Our bulky globe spins eternally eastward around the central axis that ends at the two poles. The wide equator has to spin at 1,000 miles per hour to complete each 24 hour rotation. North and south of this wide waist, smaller and smaller circles of latitude spin slower and slower. Near the poles, rotation speed diminishes almost to a standstill. If the spinning earth created a global draft, the clouds would be dragged eastward. They would whirl fast around the equator, slow down in higher latitudes and hover in motion masses above the poles. The global pattern of cloud motion, of course, does not follow these rules. So the spinning earth does not create a draft that drags the clouds eastward in diminishing global circles.

However, the earth's rotation does play a role in the cloudy picture. In fact, it plays two roles. Clouds are wafted by winds and both are children of the sun and the spinning globe. The sun warms up patches of the air during the day and the summer and over the tropics. Cooler air masses tend to blow toward warmer air masses, gathering moisture from the seas. This interaction of sun and globe creates the clouds and the winds that set them in motion.

Meantime the rotating earth spins a global pattern for the winds to Mlow. The rota

tion creates three circling belts of prevailing winds between the equator and each of the poles. The basic facts of this maneuver were explained 132 years ago by a brilliant French mathematician named Caspard Gustave de Coriolis. He explained a basic law of motion that applies to moving objects and rotating bodies. In this case, the moving objects are clouds and the rotating body is the earth below them. North and south of the equator, the rotation speed diminishes. Objects moving above the spinning surface appear to pull ahead or lag behind, depending upon whether they are moving toward or away from the equator.

This drifting relationship between the ground and the clouds is called the Coriolis effect. It deflects, or bends, the weathery events to the right above the Northern Hemisphere and to the left above the Southern Hemisphere. The speeding equator noses ahead and lines of diminishing speeds lag behind through latitudes farther north and south. The spinning earth adds a global pattern to all objects moving about it. North of the equator, the Coriolis effect bends global winds and local storms, bullets and baseballs to the right. South of the equator, it gives a leftward bend to all objects moving above the spinning surface.

The spinning earth, then, does not waft the clouds around in a whirling draft. But it does play a role, a double role, in the motion of clouds above its rotating surface. The formation of cloudy winds is very complex, for air masses rise and sink and start out in all directions. But when formed, the spinning earth draws them into planetary patterns in the opposite hemispheres.