"Malena explains that friction is like tiny trucks on the skis driving up and down on microscopic mountains on the ramp. Niels helps sand off those microscopic mountains and catches on fire while doing so. By almost causing Malena to go tumbling down the ramp, Niels learns that friction is greater with two people on one set of skis. He also learns that while lubricants can be used to reduce friction, some lubricants are more effective and less smelly and messy than others."