Great Science Projects for Kids: This solar robot, including gears, screws, solar panels and other building parts. Through assembling practice, helps children learn the mechanical transmission structure of the vehicle model, and learn how solar energy is converted into mechanical energy. It is a perfect STEM building toys for boys age 8-12 year old boys and girls.DIY building block assembly.The solar upgrade version has two sports modes that can be switched: one needs to be powered by an R6/AA/UM3 battery, and the other is powered by solar panels.This is a four-wheel drive model device, which can use the vertically moving wheels on the four corners to move forward, and can easily climb over obstacles of 50mm height.All materials required for simple snap-fit or screw-on assembly are included. Simple wiring is required to complete the assembly.3 kinds of chassis angles can be selected when setting.The power is provided by the motor and transmitted to the wheels via the assembled trapezoidal chain.