Sally Ottaway, age 11, of Wichita, Kansas, for her question

Why is the equator always hot?

The sun is hottest when it i s highest in the sky. When it is directly overhead its rays are straight through the atmosphere. When it is low in the sky, its rays slope through the atmosphere in a longer, slanting line, We live in the temperate zone, north of the tropics, and we never see the sun directly overhead. At the equator, however, the noon sun is almost overhead every day and twice a year it is directly overhead.

The equator, exactly half way between the two poles, is at the center of the earth's torrid zone. This wide belt of tropical climate extends from the Tropic of Cancer, about 23" degrees north of the equator, to the Tropic of Capricorn, about 231 degrees south of the equator. In this whole climate zone, the noon sun is never far from directly overhead. What's more the sun always rises almost due east and sets almost due west.

This tropical belt around the waist of the world enjoys the nearly direct rays of the sun every day of the year. Tropical days and nights are almost equal throughout the year. There are no short winter days as there arc in the temperate climate zones.

Land and sea areas cause variations in the climate of the tropics. Sea breezes cool certain islands and bring rainy seasons to certain coastal areas. There is, however, no cold. winter season. Though we tend to think of the tropics as sweltering in year‑round heat this is not necessarily so. Summers in certain temperate climate areas are often hotter than in the tropics because of the long summer days.

 Though every spot on earth has its own peculiarities of climate, there are three major climate zones. There are the tropics around the bulging waist of the world, the temperate zones north and south of the tropics and the frigid zones, the polar regions within the Arctic and Antarctic circles,

These major climate zones are caused because the earth’s axis is tilted to the plane of its orbit. With the north pole the top and the:. south pole the bottom, the world does not travel around its orbit in an erect position. It slopes at an angle of 231 degrees.

In January the north pole is pointing away from the sun, the south pole towards it. The north temperate zone has winter while the south temperate zone is enjoying summer. But the equatorial zone feels little of these changes. The sun is always shining on one half of the equator. As the earth rotates, first one half of the wide circle and then the other faces directly towards the sun. Days and nights are equal throughout the year and the equator does not get a chance to cool off with a winter period of short days and sloping sunshine.