Measuring Earth’s Water Activity Source: Source: NASA. Adapted with permission. 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? [Read More]

Modeling Earth’s Water — Fresh vs. Salty Activity Source: Source: U.S. Geological Survey. Adapted with permission. We drink water every day — we can’t live without it! About 70 percent of Earth’s surface is covered by water, but how much of Earth’s water is actually drinkable? In other words, how much is liquid freshwater — not salty or frozen? Materials • Globe or world map • Water cycle diagram • 100 gummy bears [Read More]