1. HYDROSPHERE Where is water on the Earth? In what forms does it exist?

3. Where is Earth's water located? Water is continually moving around, through, and above the Earth as water vapor, liquid water, and ice. In fact, water is continually changing it's form. The Earth is pretty much a "closed system," like a terrarium. That means that the Earth neither, as a whole, gains nor loses much matter, including water. Although some matter, such as meteors from outer space, are captured by Earth, very little of Earth's substances escape into outer space. This is certainly true about water. This means that the same water that existed on Earth long ago is still here. Thanks to the water cycle, the same water is continually being recycled all around the globe.

5. Earth's water distribution The left-side pie chart shows that over 99 percent of all water (oceans, seas, ice, and atmosphere) is not available for our uses. Even of the remaining 0.3 percent (the small brown slice in the top pie chart), much of that is out of reach. Considering that most of the water we use in everyday life comes from rivers (the small yellow slice in the right-side pie chart), you'll see we generally only make use of a tiny portion of the available water supplies. The right-side pie shows that the vast majority of the fresh water available for our uses is stored in the ground (the large brown slice in the second pie chart).

6. How much water is there on (and in) the Earth? As you know, the Earth is a watery place. About 70 percent of the Earth's surface is water-covered. Water also exists in the air as water vapor and in the ground as soil moisture and in aquifers. Thanks to the water cycle our planet's water supply is constantly moving from one place to another and from one form to another. Things would get pretty stale without the water cycle!

7. How much water is there on (and in) the Earth? When you take a look at the water around you, you see water in streams, rivers, and lakes. You see water sitting on the surface of the earth. Naturally, this water is known as "surface water." Your view of the water cycle might be that when rain falls it fills up the rivers and lakes. But, how would you account for the flow in rivers after weeks without rain? The answer is that there is more to our water supply than just surface water, there is also plenty of water beneath our feet. Even though you may only notice water on the Earth's surface, there is much more water stored underground than on the earth’s surface. In fact, some of the water you see flowing in rivers comes from seepage of ground water into river beds. Water from precipitation continually seeps into the ground to recharge the aquifers, while at the same time water from underground aquifers continually recharges rivers through seepage.

9. Earth's water distribution Where is Earth's water located and in what forms does it exist? You can see how water is distributed by viewing these bar charts. The left-side bar shows where the water on Earth exists; about 97 percent of all water is in the oceans. The middle bar represents the 3 percent of the "other" part of the left- side bar (that portion of all of Earth's water that IS NOT in the oceans). Most, 77 percent, is locked up in glaciers and icecaps, mainly in Greenland and Antarctica, and in saline inland seas. Twenty-two percent of this portion of Earth's water is groundwater. The right-side bar shows the distribution of the "other" portion of the middle bar (the remaining one percent). Notice how rivers make up less than 4/10th of one percent of this remaining water yet this is where we get most of the water for our everyday uses !

11. 97% OCEANS Oceans are like really big lakes. Rivers and streams carry all of the water that comes from rain and melted snow into the oceans. When water gets into the oceans, it mixes and becomes salty. When the sun shines on the oceans, the water gets warmer and becomes vapor, which goes into the air and becomes a cloud. Most of the water on the earth is in the oceans. Note: Oceans are salty because they have no outlet. Surface fresh water continually brings tiny amounts of salts to the ocean but the only way water leaves is by evaporation and that leaves salt behind.

12. 2.7% ICECAPS and GLACIERS Some of the snow that falls onto mountains stays there a long time because it is so cold most of the time at the top of mountains. This snow turns into ice and sometimes becomes glaciers. Snow and ice on the top of mountains can stay there sometimes for hundreds or thousands of years before it finally melts and runs into the streams and rivers. Greenland and Antartica are covered by ice that in many places is over a mile thick.

13. .2% GROUNDWATER What is groundwater? (1) water that flows or seeps downward and saturates soil or rock, supplying springs and wells. The upper surface of the saturate zone is called the water table. (2) Water stored underground in rock crevices and in the pores of geologic materials that make up the Earth's crust. Groundwater has infiltrated the earth’s surface.

14. .07% SURFACE WATER What is Surface Water? Surface water is fresh water on the Earth's surface, such as in a creek, stream, river, lake, swamp, pond or reservoir. This is runoff water, that did not infiltrate and become groundwater.

15. ATMOSPHERIC WATER Atmospheric water may exist as vapor. Energy from the sun adds heat to water molecules making them moving quickly. Some of them fly into the air and become vapor. Atmospheric water may also exist as liquid when water vapor rises in the stratosphere, cools, and then condenses. Clouds are made of condensed water. Atmospheric water may be ice crystals, particularly in cirrus clouds.