Kids set off a chain reaction of fun! Our set lets pre-k through second-grade students set up a course of ramps, pendulums, hammers, switches and more…then drop a ball onto the tracks and go for the goal box! After each test run, kids will fine-tune the placement, distance and angle of each piece—getting firsthand practice with STEM concepts such as gravity, force and momentum! Packed with super-durable plastic pieces, the set is perfect for open-ended building—or kids can use the leveled challenge cards to create a variety of different courses from scratch! Set comes with 67 pieces, plus 6 balls, 10 challenge cards and a guide. The tracks measure 12" in length.