Water Science for Schools. After you arrive far above the Earth's surface and look back at it, you notice that the earth appears to be a blue ball shining in a black sky. You also notice, being the bright astronaut that you are, that the blue color overwhelms any other color on Earth. Water takes up nearly three-quarters of the Earth's surface. And if you journey below ground, you'll find even more water filling the gaps between the rocks.
Rivers are one of many bodies of water that cover the Earth's surface.
Earth's rivers vary in size. Some are so small they dry up during the dry seasons. Even though the list of Earth's rivers seems endless, each river has a story behind it. The Jordan River, in Israel-Jordan, is the most mentioned river in the Bible. The Indus River, in Tibet-Pakistan, is the source of one of the largest irrigation systems in the world.