Images of the word Ã¢â‚¬Å“waterÃ¢â‚¬Â in different languages projected on a fog screen greet visitors as they enter the exhibition. Ã‚Â©D. Finnin/AMNH

NEW YORK -- On an illuminated wall in the American Museum of Natural History, three clear plastic tubes about 5-feet long and a couple inches in diameter automatically fill with water. In the first tube, a small amount shoots up, barely visible at the tube's bottom, representing the meager 3 gallons of water that the average Ethiopian subsists on daily. The middle tube fills about one quarter full, showing the more bountiful 30 gallons of water the average Briton uses in a day.

Both amounts pale in comparison when water fills to the top of the third tube and shows the astounding 150 gallons of water that the average American uses in a day.

This waste of one of Earth's most precious resources is a central theme of the AMNH's new exhibition, Water: H2O=Life. In the exhibition, visitors can explore the many facets of water: its astounding physical properties, its ability to shape ecosystems, landscapes and societies, the importance of conserving water and ultimately the fact that water is essential to life.

Water and life

Throughout the exhibition are examples of the different ways that life has evolved around the amount of water available to them. Tiny fish, adapted to live in an entirely aquatic environment, swim in tanks, while at the other end of the spectrum the Texas horned lizard, which lives in a very arid climate, has tiny channels between its scales (pictured in a display) that guide rainwater to its mouth.

In another tank, visitors can see mudskippers, an unusual amphibious type of fish, swimming through the water, then taking brief rests on rocks where they can breathe in the air.

Water is essential to life, because "every living cell is composed primarily of water," said AMNH president Ellen Futter during a press preview of the event.

We humans are two-thirds water ourselves. Visitors to the exhibition can stand on a scale that will tell them just how much water they contain (this reporter had 3. 2 gallons, or 12 liters, in her).

Water and society

Like other animals, humans have also learned to survive in lands with wildly varying amounts of water—a fact reflected in the entrance to the exhibition, which features a curtain of mist on which the words for water in many different languages are emblazoned in light: Eau. Nepo. Siram. Su. Maji, Agua. Water.

Often, the places with the most people have the least water. In some African and Asian countries, women must carry water in jugs over long distances to have enough for their families. Visitors can try to lift one of these jugs themselves, but good luck, because it holds 11 liters (weighing 25 pounds) of water.

Humans have manipulated water's sources to irrigate our crops, bolster our drinking supplies and provide us with power. We appropriate more than 50 percent of the world's surface freshwater for our needs, the exhibition notes.

Freshwater comprises only 3 percent of the water on Earth, and two-thirds of that is locked up in glaciers and polar ice caps. A projector throws images onto a giant globe (about 6 feet in diameter) suspended from the ceiling mid-way through the exhibition to demonstrate how little freshwater there is. Earth's water is broken up into grids— while ocean water takes up almost the entire globe, the proportion that is available to us looks like a blue rubber band stretched around the equator. And that amount is unlikely to get much bigger.

"Water on Earth is finite. We will never get more than we have now," said exhibition curator Eleanor Sterling, director of the Museum's Center for Biodiversity and Conservation.

To bring large quantities of this freshwater where it is needed, humans have built dams—more than 60 percent of the world's rivers have been dammed or diverted, with 47,000 large dams built in just the last 50 years. While these dams bring water to cities and crops or provide electricity, they also block migration routes for fish, flood nearby lands and create erosion downstream because they block sediments behind them.

Visitors can see the effects of dams first-hand with a model stream in a clear plastic rectangular box that has a lever that can be pulled up or down to dam and un-dam the "stream" to see how it causes a pile-up of sediment behind it.

These dams and diversions can leave some areas dried up—Soviet diversions have shrunk the Aral Sea to a fraction of its former size. With water already scarce in some areas and becoming scarcer in others due to dams or the effects of global warming, water looks to become an even more precious commodity in the future.

"Water in the future will have wars fought over it," Futter said.

This impending scarcity underscores the need to implement better water practices and conservation, Sterling says.

Water conservation

The exhibition is full of helpful tips on how to conserve water.

Touch-screen monitors let visitors take a quiz on water conservation, including questions on what do if your sink is leaking (call a plumber!), whether an 8-minute shower with a low-flow head is better than a 5-minute shower with a standard head (it is), or whether an aerator really reduces the amount of water you use (it does).

To set an example in water conservation, the exhibition uses re-circulated water in all its displays.

Because the American lifestyle relies on copious water, another interactive monitor lets visitors compete in a three-player "quiz show," with questions centering on the concept called virtual water. Water use doesn't just include what you drink from the bottle or what you use to wash your clothes. It also includes the water used to grow the things we eat and wear. If you take the quiz, remember that the average fast food meal takes nearly 3,000 liters of water to make (because of the water used to grow the corn that feeds cattle).

A movie playing constantly in one corner of the exhibition touches on the ways that agriculture (which comprises most of our use of freshwater) can institute better water practices. These include using drip irrigation instead of standard methods and growing crops in areas that having the appropriate amounts of water needed (so cotton, a very thirsty crop, should not be grown in drier areas).

To show that individuals can make a difference in water conservation, pictures at the end of the exhibition show the ways that ordinary people are reducing their own water consumption.

The American Museum of Natural History's exhibition, Water: H2O=Life opens on Nov. 3, 2007 and will appear through May 25, 2008.