Communicate scientific ideas about the way stars, over their life cycle, produce elements.
Leaf It to Me
In the water cycle, there are two ways water moves from the ground to the atmosphere: evaporation and transpiration. During evaporation, water changes from a liquid to a gas state. Transpiration is basically evaporation of water from plant leaves. Transpiration accounts for about 10 percent of the moisture in the atmosphere — with oceans, seas, and other bodies of water providing nearly all the rest.
Measuring Earth’s Water
Even though our home planet has a lot of water, over 73 percent of that is salt water. We need freshwater to meet most of our needs, and precipitation supplies much of this valuable natural resource. Did you know that NASA, in a partnership with the Japanese, has a satellite that measures precipitation as it falls from the clouds to the ground?
Water Quality, Dissolved Oxygen, and Phosphorous
Tap water from the kitchen has very different properties from water in a stream or a pond, even if they might appear similar. Water quality refers to the physical and chemical properties of water
that make it suitable for a particular use based on biological, physical, and chemical characteristics. A fish might live in sedimentrich water at the bottom of a lake, but you would not want to drink it!