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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Water Cooler: Water cycle science for kids

Charlize Wright, 9, and Jocelyn Quigley, 9, right, walk hand-in-hand as they lead 15 family members through the rain in Riverfront Park on their way to the Numerica SkyRide on Sept. 25 in Spokane. The group, from Tri-Cities, was taking a break from homeschooling and planned to also visit the Blue Zoo Aquarium at NorthTown Mall.  (DAN PELLE/THE SPOKESMAN-REVIEW)

April is known for its rain showers, but where does all that water come from? How does it get in the sky in the first place? And after it falls to the ground and forms rain puddles, where does it go? These are examples of water in various steps of Earth’s water cycle. Spring is the perfect time to learn about the water cycle because this rainy season provides many opportunities to see the water cycle in action.

On planet Earth, water is continually moving and changing states. The water cycle contains several steps that repeat over and over again, providing the distribution of water throughout the planet. The step you are probably most familiar with is precipitation in the form of rain, snow, hail, graupel (a type of soft hail), water dripping to the ground from fog (known as fog drip) and sleet, which is a sort of slushy snow. According to NASA, about 78% of global precipitation falls over the ocean. The remaining water that falls on land masses has various methods of moving and getting to the next phase of the water cycle.

Some of the water seeps into the ground to become groundwater. This is water that sits below Earth’s surface, filling in spaces between rocks and soil particles. One form of groundwater you may have heard of is an aquifer. Below the area around Spokane County and Kootenai County is the Spokane Valley-Rathdrum Prairie aquifer, spanning 370 square miles and containing about 10 trillion gallons of water. This makes it the primary water source in the area.

Aquifers are often thought of as underground lakes, but actually they are a body of sediment and rock that holds a lot of groundwater. Groundwater can be extracted for drinking water using a well or pump, although some of it naturally comes to the surface as springs or through lakes and streams. One of the easiest ways to illustrate groundwater is to dig a hole in the sand of a beach. Very quickly, you will dig deep enough to find the stored water underground.

Most of the water that doesn’t seep into the ground eventually finds its way to streams, rivers, lakes and eventually the ocean. This is called runoff, where the water runs down the land surface due to gravity. Whether the water stayed in a puddle, or became runoff that found its way to a river, it will then move onto the next step – evaporation.

Evaporation is the process of turning liquid water into water vapor. The driving force behind liquid water changing into water vapor is the sun. The sun shines on the bodies of water on Earth’s surface and heats the water up, causing it to change from a liquid to a gas state. The warm water vapor rises high up into the atmosphere where it forms clouds.

You can do a quick evaporation experiment at home by blowing your hot breath on a mirror or window. The water vapor from your breath collects on the cool surface of the glass, making a small foggy spot. This spot then cools down and the vapor changes into liquid water droplets. This is the same concept behind how clouds are made. High up in the atmosphere, the water vapor of clouds cools down and becomes water droplets. White clouds turn gray as they become heavier and filled with water. Eventually the water gets too heavy and gravity causes it to fall back to the surface of the Earth as precipitation.

The cycle continues over and over again and water travels all around the Earth. This means the water in your cup might have at one time been part of a river, lake or ocean on the other side of the globe. Keep your eye out this spring for the signs of the water cycle, from precipitation to puddles to runoff to precipitation again.