I have a group of students in a new Ag Science course this year that they weren't anticipating taking, so motivating them on certain topics has been a bit of a challenge. They do really well with projects that they can construct/build/grow - they're definitely hands-on learners. I wanted to share a project I recently completed with them that they really enjoyed! As part of our Plant and Soil Science Unit, we dived into agricultural land use and completed an "Erosion Challenge." This was modeled from a STEM project that focused on engineering concepts for urban erosion and runoff. Students "inherited" a 300 acre parcel of land, but the land was on a side hill with a lake/pond at the bottom. They had to plan, design and construct solutions to prevent runoff into the lake. The "land" was a plastic paint tray nailed to a 2"x6" board to provide an incline. The soil was basic potting soil. A picture of a student working on theirs is shown below.
A few modifications/suggestions - if you can afford it, use metal paint trays - the plastic ones worked, but were kind of flimsy as students were putting items in the soil. I didn't put water in the "lake" until just before we were testing their concepts. While constructing/building, there would have been too much of the soil lost into it. I used basic drinking straws and allowed them to use a soldering iron to put holes in it to make it like drainage tile. Wider, smoothie style straws probably would work better. They were also allowed to use limited amounts of clay to use as a base/holder for some of the items like the tree forks. They weren't allowed to use the clay as part of their design. I bought outdoor grass rug material for them to use as cover crops. It was fairly inexpensive at Lowe's. To test their designs, I used a watering can and "watered" the soil. Some worked really well, others were a disaster! We also put a fan on a few of them to illustrate the concept of soil loss from erosion by wind.