Description: DIY dual-track slope of roll up ball toy exploring barycenter ，educational physics science DIY experiments toy scene： When you separate the two tracks, the glass ball will roll upwards；As you move closer to the two tracks, the glass ball will roll downwards Exploring how to emerge such a mysterious phenomenon，Exploring how to emerge such a mysterious phenomenon Due to and angle of dual-track slope， when the Barycenter of glass ball is higher when it is at the lower height of slope, so the ball is rolling up from the slope of low to high under the action of gravity , forming " slope" phenomenon Develop children's hand & eye coordination, and help children experience the theory of power, expand kids scientific & mechanical interest White brids can be colored by yourself as you like Main Material: Plastic Color：Multicolored Specification: Need to be assembled by yourself: assemble the model as the pictures shown Size Chart: Slope size (L*W): Approx 24*8*6cm/ 9.44*3.14*2.36 inch Ball(Dia) Approx 2.5cm/ 0.98 inch Package Includes: 1 Set Slope of Roll Up Ball Toy (with assembled picture instructions) : Due to the manual measurement, please allow 1-2mm differences in size Due to the light and screen difference, the item's color may be slightly different from the pictures. Please understand