In New York, the water cycle is taught in 4th grade, although in practice it often happens earlier than that. Students are taught that due to a series of forces, water cycles through the Earth and never disappears.
The problem with this explanation of the water cycle is that it doesn’t quite account for water conservation – if water is infinitely recycled throughout the Earth, then what’s the danger of taking a 30 minute shower? I didn’t “waste” the water because it can never go away!
This very valid question requires a more nuanced understanding of the water cycle. Yes, it is the case that water never disappears from the Earth. However, human beings do still “use” water with potentially negative consequences, including the following:
- The water that evaporates does not necessarily fall down straight where it evaporated. Water moves through the air. If individuals living the desert use up all their groundwater to water artificial lawns, the water that evaporates will rain on a different part of the world and the desert town will be even drier than it was before.
- When humans interact with water, they run the risk of polluting the water. Whether its poop, fertilizers, soap, or something else, every time we use water to flush our toilets, water our plants, or wash our hands, we add chemicals to the water. Those then have to be filtered out before the water can be safely returned to the rivers, lakes, and oceans around us. This process of treating the water is time consuming and expensive. The less water you use, the less treatment is needed, the more water is available for future use by humans, other animals, or plants.
Like many things we teach children, the water cycle is both simple and complicated. Giving students a more complicated picture of water will help them understand the semi-paradox that no water ever disappears, and yet we can waste water.
Tomorrow, we will return to the water cycle with a great water cycle game for students of all ages.
PS: For a water cycle resource for early childhood, check out Round the Garden, which tells the story of the water cycle through gardening.
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