Modeling Erosion for Understanding

Science teacher James Audrain leads 4th grade scientists in a year-long investigation of the ways people engineer the world. He asks students to explore features of the Earth’s surface and rapid and gradual processes of change, like plate movement, volcanic eruptions, natural hazards and weathering and erosion. Students apply their knowledge and design solutions to diminish the impact of these processes on humans.

To help his students understand how changes in rivers occur both naturally and as a consequence of human activity, Audrain set up a stream table in the center of his classroom, traced a path in the sand for a river to flow and turned on the water. In time, the light-colored soil became dark and saturated with water, and eventually a small river began flowing along the line. Audrain invited students to construct a building using LEGOs and place it in the stream table along the river in a suitable location. As the water continued to flow, soil that once seemed sturdy and reliable began to erode beneath the LEGO structures, causing some of them to lean or fall down completely. 

Audrian said, “As students learn about the changes and natural hazards of rivers, they design modifications to their buildings to see if they can mitigate the problems—like stilts under houses and deeper foundations to ‘bedrock.’” Audrain worked with students to test their revised designs on the stream table by increasing water flow to cause flooding. He also shared photos of real-world examples from places he has visited, like the Darien Gap, which feature stilted houses built along waterways. 

As a final project, Audrain will challenge students to build a model “amphibious” house out of LEGOs that can float up and down as the water level rises and falls, based on the examples he shared in class.

“Experiences like this help students to understand that nature is vibrant and active and that change is a part of nature,” Audrain said. “The more we avoid working against the cycles of nature, and learn to support and work with nature—instead of trying to control it—the easier it is for us and nature.”

View photos from the stream table curriculum here.