Physics is fun! With a track length of nearly 15 feet, the three different action courses offer boundless marble ball run fun. The four educational experimental models also indirectly explain the effects of different physical phenomena (acceleration, inertia, balance of forces, principle of conservation of energy, principle of linear momentum, laws of motion). The eLearning portal (fischertechnik-elearning.com) features interesting, educational information and videos about physics. Main subjects: Centrifugal force /force of gravity /acceleration /law of conservation of energy / pulses. Includes instructional activity information (free download). 780 components for building 7 different models. Parts include an XS motor, 4 high-speed curves, 17 flex-rails 180, 8 flex-rails 90, 10 metal balls, 3 180° curves, 4 90° curves, a cross-over, a catch funnel, and a battery tray for 9V block (battery not included). Ideal additions: Sound+Lights, LED Set, Accu Set or Power Set (each sold separately).