K12: Grade 5: Lesson 1: Freshwater

Water is critical to sustaining life on earth. The human body relies on water. We need water to grown food. How is it that only one percent of all of the water on earth is freshwater? 

Almost 75 percent of the Earth's surface is covered by water. About 96 percent of it is ocean water. That leaves only 4 percent of all water in the form of freshwater, but 3 percent of this freshwater is frozen in glaciers and polar ice. Only 1 percent of all the water on Earth is usable freshwater. 

The Basilica Cistern, located in Istanbul, Turkey, was built in sometime in the 3rd and 4th centuries during the Early Roman Age. It is the largest of several hundred ancient cisterns in Turkey. These ancient cisterns provided life giving water during hard times to ancient peoples.