Gravitrax makes physics feel like play

The Gravitrax Starter Set is one of those rare toys where the kid doesn’t realize they’re learning. They build marble runs, experiment with height and momentum, and figure out cause and effect — all while being completely absorbed in the construction. The pieces snap together solidly and the expansion packs let you grow the system over years. My kid went from asking “how does this work” to explaining potential energy to me at dinner.