Tap Into Quality Quiz on QuizRevolution

All living things need water. In some organisms, (like jellyfish!) up to 90 percent of their body weight comes from water. Up to 60 percent of the human body is water, and the brain is composed of 70 percent water! Our blood is 82 percent water and our lungs are nearly 90 percent water.

Water's chemical formula is H2O. One atom of oxygen binds to two atoms of hydrogen. The hydrogen atoms are "attached" to one side of the oxygen atom, resulting in a water molecule having a positive charge on the side where the hydrogen atoms are, and a negative charge on the other side, where the oxygen atom is. Since opposite electrical charges attract, water molecules tend to attract to each other, making water kind of "sticky."

Salt in the ocean comes from rocks on land. The rain that falls on the land contains some dissolved carbon dioxide from the surrounding air. This causes the rainwater to be slightly acidic due to carbonic acid (which forms from carbon dioxide and water). The rain erodes the rock and the acid breaks down the rocks and carries it along in a dissolved state as ions. The ions in the runoff are carried to the streams and rivers to the ocean. Many of the dissolved ions are used by organisms in the ocean and are removed from the water. Others are not used up and are left for long periods of time where their concentrations increase over time.

About 41 percent of the earth's water is used for agriculture, 39 percent for hydroelectric power, 6 percent for industrial use, 6 percent for household purposes like showers, dishwashing, and goldfish, and only about 1 percent for drinking water!

As early as 300 A.D., the Hohokam began to construct the first canal systems in Central Arizona. They diverted water from the Salt, Gila, and Verde rivers for agricultural and other uses.

The Hydrologic Cycle, also known as the Water Cycle, recycles the earth's valuable water supply. In other words, the water keeps getting reused over and over again. The first step in this process is evaporation. Evaporation turns water from a liquid to a gas, or "vapor." Warm air currents rising from the earth's surface lift this water vapor up into the atmosphere.

The earth's ground water supply is one of the world's largest storehouses of water. Ground water is the part of precipitation that seeps down through the soil until it reaches areas saturated with water, where it collects. Ground water slowly moves underground, generally at a downward angle (because of gravity), and may eventually seep into streams, lakes, and oceans.

In the Phoenix area, Salt River Project (SRP) and Central Arizona Project (CAP) manage the delivery of the raw water (from CAP, SRP, and SRP Wells) through a series of canals to each water provider's treatment facility, where water industry professionals work hard to assure that all water meets or surpasses the rigorous standards set by federal, state, and county regulatory agencies.

The use of Chlorine as a disinfectant has been around for about a century, and is responsible for greatly reducing waterborne diseases. Chlorine is effective against almost all bacteria, amoebas, and viruses. As a result of widespread use of chlorination practices in the United States, cholera, typhoid fever, dysentery and hepatitis have been virtually eliminated as a threat to public health.

As water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. Calcium, magnesium, potassium, and sodium are the most common compounds that make water "hard." Hardness is sometimes measured by the amount of Total Dissolved Solids (TDS) found in water.

Thanks to the Hydrologic Cycle, a simple glass of water could have been a liquid, a solid, and a gas countless times over. Water can be in the form of vapor (gas) due to evaporation, in the form of drops (liquid) due to condensation and precipitation, or in the form of ice (solid) due to atmospheric conditions such as freezing temperatures.

Only 1 percent of the water on Earth is fresh. The remaining water exists as salt water (97 percent) and frozen water (2 percent). The U.S. has fresh water resources totaling about 660 trillion gallons!