The Wonder of Water Water covers 70 percent of Earth’s surface. So why do the people of Marsabit struggle to get enough of it? We can’t use most of Earth’s water. Nearly 97 percent is salty or otherwise undrinkable. Another two percent is locked up in glaciers and ice caps. T at leaves only one percent. People, plants, and animals depend on that one percent of fresh water. Each drop of water is always on the move.


T e water we drink is a liquid. It can also be a solid or a vapor. No matter what state of matter it’s in, all water is connected. It constantly moves through an endless cycle above, on, and through Earth. For example, when the sun beats down on


the ocean, water evaporates. It rises into the sky as vapor. T e vapor forms clouds. Later, the vapor condenses and falls as rain or snow. Next thing you know, you’ve got an indoor recess! T e rain and snow soak into schoolyards, soccer fi elds, and lawns. Water seeps into creeks and rivers. T en it fl ows back into the ocean.


Quenching the Thirst Water has been recycled like this for millions of years. T e amount of water on our planet never changes. T ere is the same amount now as there was when Earth formed. T e water that drips from your faucet today could be the same water that dinosaurs drank long ago. All living things need water to survive and


that includes plants. In some plants, roots suck up water from the ground. In other plants, leaves and stems take in water. On a hot summer day, a thirsty birch tree can take in 300 liters (80 gallons) of water from the ground. T at tree can then release almost the same amount into the air as water vapor. In dry places, plants must make every drop


count. A desert cactus’s leaves store water. Some plants become dormant, or “hibernate,” during extremely dry times. When rain fi nally falls, they burst back to life in an explosion of color. Plants use water to spread their seeds, too.


Rivers and oceans are seed superhighways. T ey can take plant seeds to far-away places. Some plants make seeds like coconuts that fl oat. T ey have a woody, waterproof covering. T is lets them bob along in salty water for long periods. When they reach land, they can take root.


A Little at a Time Where there’s water, animals can’t be far behind. Water helps animals take in nutrients and get rid of waste. It helps them keep cool on hot days. If water is hard to fi nd, animals must conserve, or save, water. A camel can go without drinking water for


a long time—sometimes as long as six months. It also saves water by not sweating. How? A camel can change its body temperature during the hottest part of the day. T is keeps it from overheating. Because it does not need to sweat to cool itself down, it saves water. Camels are not the only animals that have


Fresh water is trapped in this iceberg in Antarctica.


20 NATIONAL GEOGRAPHIC EXPLORER


unique water ways. T e kangaroo rat seldom drinks water. Instead, it gets water from the plants it eats.

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