Wheels for a Mousetrap

All Grade 8 students were challenged to build a mousetrap-powered car.  Then, they have to race them down a long school hallway to see which one travels the farthest.  S & P discussed design and physics for ages and came up with a car that releases the mousetrap after the wire comes to an end, like the space shuttle fuel tanks fall away mid-launch.  Here's the second try.