Kristena Kirkland, age 14, of Venice, Florida, for her question:

How do temperatures differ in the two hemispheres?

The seasonal temperatures alternate as the sun moves north and south of the equator. Hence, the Southern Hemisphere gets its summery weather while we are suffering through the winter. Other variations in the two hemispheres occur for geographical reasons, especially the unequal distribution of land and sea areas north and south of the equator. The Northern Hemisphere has the lion's share of the land. However, its polar region is under the Arctic Sea while the South Pole is in the midst of frozen Antarctica.

The temperature ranges on land are more extreme than those of the seas. North of the equator, the continental temperatures are quite similar to those of South America, Africa and Australia. But the southern continents are surrounded by much larger oceans, where the seasonal temperature changes are more moderate. However, Antarctica is a frozen land mass, much colder than any place north of the equator. The Arctic Sea brings milder winters to the north polar region.