D. The Hydrosphere 1. 70% of the Earth is water a. 97 % of that is salt water 2. Water in the ocean is 77% NaCl a. aka table salt

3. Freshwater is extremely limited so it is valuable a. Can be as surface or ground water b. Aquifer- underground river 1. If you drill here you get an artesian well that flows to the surface

E. The Water Cycle 1. Also called the hydrologic cycle 2. Cycle of water between the land and atmosphere

3. Consists of many steps a. Water sits in large pools b. Heat evaporates water to form clouds c. Clouds become full and release water as precipitation d. Water returns to earth and runs into streams and rivers e. Streams return to the large pools

4. A significant amount of water in the 4. A significant amount of water in the soil evaporates through leaves of trees a. This is called transpiration 5. Most of the world freshwater is locked in glaciers and does not participate