WALNUT — Bureau Valley North seventh-grade science students have been learning about Newton’s three laws of motion.  Newton’s three laws seem to work perfectly on the chalk board, but in real life surfaces are seldom frictionless few moving objects are truly predictable. This is because outside forces interfere with Newton’s perfect situations. Balloon racers rely on Newton’s third law of motion. As the air rushes backward out of the balloon, it pushes the car forward in the opposite direction with an equal force. The seventh grade’s job was to make the most of this force. While building balloon racers, they were able to discover how difficult it can be to make something work reliably.