Included are two charts that can be used to test your students' ability to calculate speed and convert units of length (customary or metric). I had my students use half of a pool noodle as a ramp. They calculated the speed at which their marble traveled down each ramp (they needed to create ramps with 4 different slopes). They then had to convert their distances into different metric units, however customary units can be used as well. The second chart is blank so you can decide which units of length you want to students to covert to.
Materials needed for this low prep:
Ramps (I used pool noodles cut in half)