water

There is nothing in the world like water. Without it, our world would be a very different place. Water covers over two-thirds of Earth and makes all life possible. It shapes our planet's surface, carving canyons and moving continents. It works with the Sun's energy to control our climate. And it is essential to our survival, as well as for food, transportation, sanitation, and even power. We need to conserve and protect this precious resource.

Definition: an odorless, tasteless substance that is essential for all plant and animal life
Chemical formula: H2O (two hydrogen atoms bonded with a single oxygen atom)
States: solid (ice), liquid (water droplets), and gas (water vapor)
Climate: Ocean currents and sea ice play a key role in regulating Earth's climate.
Cool fact: Water is found in all living things. Two-thirds of the human body is made of water.

Image credits: main image, courtesty of AMNH / C. Chesek; Eleanor Sterling: courtesy of AMNH; Eleanor Sterling: courtesy of AMNH.