Transcript Hydrosphere
After your test . . . Using the Parts of a River Vocabulary draw a diagram of a River System. Diagram must include all of the Vocabulary provided and must be labeled. Pages 15 & 49 can help with your diagram. The Four Spheres of the Earth • Atmosphere: the air • Lithosphere: the earth’s crust • Hydrosphere: Oceans, lakes, rivers and other bodies of water • Biosphere: the part of the earth that supports life Atmosphere A “pause” is about 6 to 8 miles in layer thickness The Hydrosphere • About 70% of the earth’s surface! • Factor for settlement. The Water Cycle • Run and get a glass of water and put it on the table next to you. Take a good long look at the water. Now -- can you guess how old it is? • The water in your glass may have fallen from the sky as rain just last week, but the water itself has been around pretty much as long as the earth has! The Water Cycle Evaporation • The water cycle has no starting point. But, we'll begin in the oceans, since that is where most of Earth's water exists. The sun, which drives the water cycle, heats water in the oceans. Some of it evaporates as vapor into the air. Evapotranspiration • Water transpired from plants and evaporated from the soil. Do plants sweat? Condensation • • • Water vapor in the air gets cold and changes back into liquid, forming clouds. This is called condensation. Air currents move clouds around the globe You can see the same sort of thing at home... pour a glass of cold water on a hot day and watch what happens. Water forms on the outside of the glass. That water didn't somehow leak through the glass! It actually came from the air. Water vapor in the warm air, turns back into liquid when it touches the cold glass. Precipitation • Precipitation occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow. Collection • When water falls back to earth as precipitation, it may fall back in the oceans, lakes or rivers or it may end up on land. When it ends up on land, it will either soak into the earth and become part of the “ground water” (infiltration). Some water infiltrates deep into the ground and replenishes aquifers (saturated subsurface rock), which store huge amounts of freshwater for long periods of time. Some infiltration stays close to the land surface and can seep back into surface-water bodies and some ground water finds openings in the land surface and emerges as freshwater springs. Over time, though, all of this water keeps moving, some to reenter the ocean, where the water cycle "ends" ... oops - I mean, where it "begins." Bodies of Salt Water • Oceans About 97 percent of the hydrosphere is a huge body of salt water divided into five oceans: the Atlantic, the Pacific, the Indian, Southern and the Arctic Oceans. • Seas, Gulfs, and Bays Large bodies of salt water partially enclosed by land comprise seas, gulfs, and bays How can we use this water? Desalination: converts ocean water into drinking water Why aren’t we all doing this? Water Shortages • How can human actions affect our water supply? • Does the water disappear during a drought? • Water from Thin Air?