Child powered marble lift

thingiverse

Create a marble lift for your child by attaching a 1L pop bottle to a stainless-steel curtain rod using a u-bend pipe. The pop bottle acts as a makeshift air pump, while the curtain rod serves as the main pipeline for the marbles in your DIY marble run. Secure the pipe and rod with hose clamps, and attach the top piece to direct the marbles downwards. To use it, simply drop marbles into the bottle, place the cardboard tube over the top, and watch them launch! However, note that this design is untested as the author doesn't have a 3D printer; consider making two if someone else is creating one for you.