Engino Discovering STEM 太陽光発電：9歳以上向け教育工学おもちゃ（16モデル）

My 9-year-old built three of the 16 models on his own in one afternoon, and the solar panel was powerful enough to spin the motor even through a window on a cloudy day. It's a great way to show how sunlight converts to electricity, though you'll want to keep the pieces organized since they're small.

The 3V solar panel actually runs the motor directly — my son was amazed when the model moved just from sunlight. We've built three models so far, and each one works differently. Great for a curious 9-year-old.

My 10-year-old built the windmill model first and was genuinely amazed watching it spin from just the 3V solar panel in direct sun. There are 16 builds so it's kept him busy for weeks instead of getting tossed aside like most kits.