Water is the clear liquid that fills rivers, lakes, and oceans, falls as rain, and makes up most of your body. Every living thing on Earth needs water to survive. Plants draw it up through their roots, animals drink it to stay alive, and your own body is about 60% water.

Water has unique properties that make life possible. It freezes into ice at 32°F and boils into steam at 212°F. Unlike most substances, water actually expands when it freezes, which is why ice floats and why a full water bottle left in the freezer might crack open. Water dissolves more substances than any other liquid, carrying nutrients to plant roots and helping your body transport vitamins and minerals where they're needed.

The same water molecules have been cycling through Earth for billions of years. Water evaporates from oceans, forms clouds, falls as rain, flows through rivers back to the sea, and repeats endlessly. The water you drink today might once have filled a dinosaur's watering hole or floated in a cloud over ancient Rome.

To water something means to give it water, like watering plants in a garden. When your eyes water, they produce tears. And when you water down an idea or story, you weaken it by removing the most interesting or important parts.