A favorite app used in our classroom is Monster Physics. The app allows students to build various contraptions including cars, cranes, rocket ships, tanks, planes, and helicopters using an assortment of parts made from different materials. The parts are connected by welding them together, drawing chains or ropes between them, or using special joints. After completing an invention, students test their creations. In addition to learning and applying physics concepts, students using creative-thinking and problem-solving skills. We use the lite version, and you can check out how Mac and Jack have been tinkering with the app in the video posted below. Below that video is a promotional video of the full version of the app, showcasing the additional features.