G5 The Water Cycle & Earth’s Spheres – 03
Once on the ground, water’s journey continues. Some of the water that falls to the ground may run across the surface. This process is called runoff. The liquid water travels to a river, lake, or ocean. Runoff may pick up fertilizer and other pollutants and deliver them to the water body where it ends up. In this way, runoff may pollute bodies of water. Water can also seep into the ground in a process called infiltration. Some of the water may seep deep underground. In the field of Earth Science, the geosphere refers to the parts of our planet that are solid, such as Earth’s crust. Some may stay in the soil, where plants can absorb it with their roots. Underground water is a common source of drinking water.
The image below lets you see the water cycle. In the image, it looks like the water cycle occurs mostly over land. That is far from the reality. In fact, most of the water that is recycled never reaches land. Why do you think this is? Here’s a hint: think back to how much of Earth is covered by water. Oceans cover about two thirds of Earth’s surface. As a result, most evaporation comes from oceans. Most precipitation falls back into the ocean.
The water cycle is a never-ending cycle between Earth’s spheres. It has no beginning or end. Most of the water you drink may be billions of years old. You now know it’s okay to drink. The water has been through a recycling process. That’s good news when you think about where this water has been. The water you are drinking may have once quenched the thirst of a dinosaur.