DIY Cardboard Marble Run

Build a gravity-defying track using cardboard tubes and tape. You will explore engineering design and physics by figuring out how to get a marble from the top to the bottom without it falling off!

Tools

• scissors
• ruler
• pencil
• markers (assorted colors, 5)

Materials

• cardboard tubes (toilet paper or paper towel rolls, 10-15)
• masking tape (1 roll)
• marbles (1 inch diameter, 3)
• large cardboard box or wall space (approx 3 feet x 3 feet)

Safety

• Adult supervision required when using scissors.
• Choking hazard: Marbles are small and should not be placed in mouths; keep away from very young children.
• Adult supervision required for sharp objects.
• Small parts pose a choking hazard. Supervise young children.
• Adult supervision required for children under 8.

Steps

1. Prepare your tubes by cutting some of the cardboard rolls in half lengthwise to create open-top U-shaped tracks.
2. Find a vertical surface to build on, such as a large cardboard box or a wall (with parent permission).
3. Tape your first tube (the starting point) high up on the wall at a slight downward angle.
4. Place a marble in the first tube to see where it lands, then tape the second tube directly underneath the end of the first one to catch the marble.
5. Continue adding tubes, experimenting with different angles. If the marble moves too slowly, make the slope steeper; if it flies off the track, make the slope gentler.
6. Create 'turns' by curving the tubes or placing them at 90-degree angles to change the marble's direction.
7. Use the markers to decorate your track or label the 'Start' and 'Finish' lines.
8. Test your run by dropping a marble at the top. If the marble falls off, analyze the gap and adjust the tape or the angle of the tubes until it works perfectly.