Jimmy Savage, age l0 from Boston, Mass., for his question:

What are cold and warm weather fronts?

All over the earth, the air is being warmed or chilled by the ground below it. The air above the frozen north becomes chilled in layers reaching high above the earth. A mass of air sitting upon the regions of the equator becomes warmed through and through.

Sooner or later, these masses of warmed or chilled air begin to move. In the Northern Hemisphere, the warmed air from the equator has a tendency to move northward in a westerly direction. The cold air from the polar regions tends to move southward in an easterly direction. The west and east twists are given to the moving air masses by the rotation of the earth,

These vast oceans of air press forward like huge incoming tides. They bring with them the cold and warm fronts which disturb our weather. These fronts are just where you would expect them to be  ¬leading the parade. They push on into the air ahead, causing disturbances, upheavals and weather changes.

From time to time, a mass of cold air from the north meets with a mass of warm air from the south. Then we get a vast weather franc stretching possibly hundreds of miles. Changes and disturbances swing the stormy front this way and that. Maybe the whole continent is in for a spell of stormy weather.

The weather upset is caused by the furious clashes between the two masses of air. Warm air is lighter than cool air and tends to rise. Often it undersides the mass of cool air and shoves it upwards into high, heaving waves. Turbulence begins high in the air as the two opposing armies of warm and cold start to mix, clash and do battle.

Then, too, warm air can hold more moisture than cool air. As warm, moisture ladened air cools it is forced to give up same of its water. The southern air mass tends to be damper than the chilled polar.  In the clash and turbulence the polar air warms itself on the warm southern air, stealing its heat, As the warm air becomes colder it must drop its overload of moisture and down comes the rain.

Weathermen all over the world check the progress of the moving weather fronts. They are spotted as soon as they start to move and step by step their journeys are noted on the weather maps. The weatherman has a good idea where they will be tomorrow and the next day, when and where two weather giants will meet. He knows what to expect of them and how they will behave and he uses this knowledge to predict the weather.