Our Balancing Bird Puzzle is a wonderful do-it-yourself physics puzzle for students of all ages. Comes with four pre-cut wooden pieces, four ceramic ring magnets and assembly instructions. No glue required. After they build their wooden birds, students must set the magnets along the bird's wingspan to determine its center of gravity. But where, exactly, should those magnets be placed? That's where the fun - and learning - begins! Measures approx. 15 cm (6") tall with a "wingspan" of 20 cm (7.875").