Design, test, and compare at least two erosion-barrier designs using a fair test, and identify which one worked better.
If moving water can erode soil, then maybe something can also stop or slow it down. Real engineers design barriers, like rows of rocks, planted grass, or walls, to protect hillsides, riverbanks, and beaches from erosion. This week, you get to test your own barrier designs.
To compare barriers fairly, you need to pour the same amount of water the same way each time, changing only the barrier itself. That is the only way to know which barrier design really works best, and which one just gets washed away.
Mastery looks like: They test and compare at least two erosion-barrier designs using a fair test and identify which one worked better, with a reason.
Common stumbles: Changing the amount of water between tests, which makes the comparison unfair; choosing a barrier material that water can simply wash away instead of actually blocking it.