Students perform several water quality tests on groundwater from their area. They use test strips to determine the pH, hardness, alkalinity, nitrates, iron and chloride levels.

Animation and text explain the water--or hydrologic--cycle, which is the process that water undergoes in nature.

A quick summary of the water cycle that includes a diagram of the cycle, with links to in-depth explanations of each component of the cycle. Click "water-cycle home" to access water-cycle resources in a variety of languages.

An in-depth explanation of the Earth's water cycle, including a hyperlinked diagram that provides direct access to information about each phase in the cycle.

Describes the four main stages of the water cycle - evaporation, condensation, precipitation, and collection.

Simple diagram and explanations of the water cycle and related terms.

The paths that water can take through Earth's systems are many and complex. Examine the following diagram from NASA depicting the water cycle. Studying the water cycle is important because changes in the water cycle affect all parts of...