periodicity

This title introduces readers to basic weather cycles, including seasonal changes and the effects of geography on local climate.

Water is essential to life on our planet. Water is constantly moving between Earth's surface, the air, and the ground. But did you know that water cannot be created or destroyed? Or that water is not only a liquid but also a solid and a gas? See the water cycle in action in this fascinating book.

Describes how the earth's motion is responsible for three cycles: day and night, the phases of the moon, and the seasons.