A video spelling out the scientific reason for the four seasons. Understand why it is summer in the United States at the same time Australia is experiencing winter. [5:38]

This brief video segment produced for Teachers' Domain features time-lapse video of a sunrise and a sunset. [1:06]

"There are four major seasons in a year- Winter, Summer, Fall, and Spring. In many places in the world rains (rainy time) are considered to be a separate season. These seasons on the earth happen due to earth's movement around the Sun...

Learn the real reason why seasons change throughout the year.