Mini catapult... this could be something really fun to make for a lesson that is a collaboration with a history class. Students could make this one, then take what they learned to design a different one! This definitely promotes students' skills in analyzing, problem-solving, and collaboration with each other!
Soil Erosion Experiment This might look like such a simple experiment but it will definitely show the importance of having vegetation covering the soil to your kids! They will love this hands on experiment!