Susan Feyke, age 13, of Spokane., Washington for her question:

How do the spring and fall equinoxes differ?

Both equinoxes bring equal day and night periods to the entire globe. The difference lies in what comes before and after these events. And this depends on the sun's position in the sky. The noonday sun is directly overhead only within the tropics. But throughout the year this position traces a path to and fro between the Tropic of Cancer and Capricorn. It crosses the equator twice, bringing the equinoxes.

After the spring equinox, the sun's path inches north of the equator. Each day it climbs higher in the sky, bringing the longer days of the summer season to the Northern Hemisphere. When the noon sun is directly overhead at the Tropic of Cancer, its path. returns to the equator in time for the fall equinox. Then winter approaches the Northern Hemisphere while spring moves south of the equator. When the noon sun is directly overhead at the Tropic of Capricorn, its path returns. north anal crosses the equator and the spring equinox returns.