I developed this project when I was tired of the typical PE/Work lab where students climb the stairs. It's my best selling item for a reason. It's fun for students, the only real cost is for masking tape and or hot glue, and it's easy to grade. :) Depending on your schedule, it can fill 3-5 class periods. Students calculate gravitational potential energy, expected exit velocity, actual exit velocity, kinetic energy on exit and energy "lost" due to friction and sound.Students use paper book