Week 2: Clean is Green

Today we talked about water pollution. This was a great follow-up to our first class when we talked about ecosystems, because the kids already understand how actions in one part of an ecosystem can affect another part.

First we talked a little about water -- why it's important to living things, and what happens when it isn't clean.

Then, we divided into small groups to conduct a scientific experiment to see how pollutants can get into our water. First, we made some hypotheses. The kids had great ideas about how litter, motor oil and chemicals get into the water! Then, we tested our ideas with a model of a watershed.

We observed how the rain water flows into the riverbed from uphill sources.

Then, we added a "pollutant" to the land uphill from the river. (It was green food coloring, but we pretended it was fertilizer from a lawn.) We observed what happened when the rain fell onto the fertilizer: it carried the fertilizer from the source, downhill into the river.

Check out these smart scientists: Hunter, Elena and Audrey.

Next, each group added soil to the land uphill from the river to represent erosion, and observed what happened when the rains came. (Did you know that sediment is the leading cause of water pollution?)

George is sharing his observations about soil erosion.

We had an interesting afternoon together. Next week, if the weather cooperates, we will talk about solar energy and make a snack with a solar oven!