Build your own solar-powered models and discover how solar cells generate electricity from light. Build six solar powered models including a locomotive, single-prop plane, bulldozer, helicopter, backhoe, and twin-rotor helicopter. The special solar panel in this kit consists of three solar cells and generates 1.5 volts of electricity in bright sunlight, like a AA battery. A unique cradle holds either the solar panel or the battery, allowing you to switch out the solar panel for a AA battery (not included), depending on the strength of sunlight. You can even use the solar panel to charge up your own rechargeable AA batteries. The solar panel is positionable, so you can experiment by adjusting it to different angles thereby maximizing its exposure to the sun to generate more power. After you have built the suggested models, you can design your own solar vehicles. Compete with your friends to see whose solar vehicle runs the fastest! 24-page color instruction book. 177 building pieces.