Develop a model to describe the cycling of water through Earth's systems driven by energy from the sun and the force of gravity.

Earth's Hydrologic Cycle

The ocean is the key element in Earth's hydrologic cycle (water cycle). Students will construct a simple model of the hydrologic cycle to help them visualize and understand the movement of liquid water and heat.

Groundwater Movement

Water that accumulates beneath the surface of the Earth is called groundwater. Contrary to popular belief, groundwater does not form underground "rivers," but is actually found in the small spaces and cracks between rocks and other material such as sand and gravel. The following activity involves learning how water moves through rock materials such as sand, gravel, and clay.

Properties of Fresh Water and Sea Water

The students will set up three demonstrations to observe the properties of water. They will explore the boiling point of water, the freezing point of water, and the ability of water to store heat. These activities can be done individually or as a set.

Sea and Ice Salinity

What is sea ice? It is simply frozen ocean water. Why is sea ice important? While it occurs mainly in polar regions, sea ice influences our global climate. Changing amounts of sea ice can affect ocean circulations, weather patterns, and temperatures around the world. Sea ice insulates the relatively warm ocean water from the cold polar atmosphere, except where cracks in the ice allow for the exchange of heat and moisture. The exchange of salt between sea ice and the ocean alters the density of ocean waters, thus influencing ocean circulation. Many animals, such as polar bears, seals, and walruses, depend on sea ice for their habitat. These species hunt, feed, and breed on the ice. Satellites provide the best way to observe sea ice, the factors that affect sea ice, and the ways sea ice affects global climate. Scheduled to launch in 2010, NASA’s Aquarius mission will measure global sea surface salinity with unprecedented resolution. Even small variations in sea surface salinity — the amount of salt present near the ocean’s surface — can have dramatic effects on sea ice, the water cycle, and ocean circulation.

Water: A Never-ending Story

Water on earth is used over and over. The water cycle, the continuous movement of water from ocean to air and land then back to the ocean in a cyclic pattern, is a central concept in meteorology.
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