Standard 4: Students will understand that water cycles through and between reservoirs in the hydrosphere and affects the other spheres of the Earth system.

Objective 1: Explain the water cycle in terms of its reservoirs, the movement between reservoirs, and the energy to move water. Evaluate the importance of freshwater to the biosphere.
a. Identify the reservoirs of Earth’s water cycle (e.g., ocean, ice caps/glaciers, atmosphere,
lakes, rivers, biosphere, groundwater) locally and globally, and graph or chart relative amounts in global reservoirs.
b. Illustrate the movement of water on Earth and describe how the processes that move water (e.g., evaporation of water, melting of ice/snow, ocean currents, movement of water vapor by wind) use energy from the sun.
c. Relate the physical and chemical properties of water to a water pollution issue.
d. Make inferences about the quality and/or quantity of freshwater, using data collected from local water systems.
e. Analyze how communities deal with water shortages, distribution, and quality in designing a long-term water use plan.

Objective 2: Analyze the physical and biological dynamics of the oceans.
a. Describe the physical dynamics of the oceans (e.g., wave action, ocean currents, El Nino, tides).
b. Determine how physical properties of oceans affect organisms (e.g., salinity, depth, tides, temperature).
c. Model energy flow in ocean ecosystems.
d. Research and report on changing ocean levels over geologic time, and relate changes in ocean level to changes in the water cycle.
e. Describe how changing sea levels could affect life on Earth.