How to Build a Marble Run from Cardboard Tubes

Learn how to turn recycled cardboard tubes into an exciting, gravity-defying marble run for your favorite marbles. HowTo: Family Edition: family how-tos that actually help.

1. Prepare your track pieces. Use your scissors to cut some of your tubes in half lengthwise, creating U-shaped channels. This makes it easier to see the marble as it rolls down the track.
2. Build your support pillars. Keep some tubes whole to use as vertical pillars. Tape them upright onto your base board at different heights to create a slope for your track.
3. Connect the tracks. Tape your U-shaped channels between the pillars. Make sure each piece is slightly lower than the one before it so gravity can pull the marble down.
4. Test and adjust. Gently drop a marble at the top of your run. If it gets stuck, check the angle of your tubes and make sure the connections are smooth.