Tumbling box
A small closed paper tube with a marble inside that somersaults all by itself down a slope.
Age : age 5+ with a grown-up for the scissors; the marble is not for under-3s
Materials
- Thick paper: card folder, card stock or 160–200 gsm paper : Thin paper gets squashed and traps the marble.
- A marble about 1.5 cm across : It must roll freely inside the 1.9 cm tube.
- Clear tape
- Scissors
- Ruler and pencil
- A board or big book covered with felt or foam : On a smooth surface the box slides instead of tumbling.
- Markers or stickers : Optional: decorate without weighing down one side.
Steps
Make the box
- Draw a 9.5 × 9 cm rectangle on the thick paper and cut it out.
- Along the 9.5 cm side, draw a line every 1.9 cm: you get 5 strips.
- At both ends, cut along each line for 1.5 cm (red lines on the template): these make the flaps.
- Score the folds by running an empty pen along each line against the ruler, then fold.
- Make a square tube: the 5th strip slides under the 1st. Tape along the whole length.
- At one end, fold the 4 flaps inwards, rounding them a little, then tape.
- Drop in the marble, then close the other end the same way.
- Decorate if you like, evenly on all four sides.
Make it tumble
- Set the felt-covered board on a gentle slope: one book under one end is enough to start.
- Put the box at the top, lying along the slope, and let go.
- Adjust the slope: too steep and it slides; not steep enough and it stops.
The marble rolls to the low end of the tube and shifts the weight there. The box tips over that end, the marble rolls to the other end, and it all starts again. It's the idea behind old-fashioned tumbling toys.
Going further: compare a glass marble and a steel ball, or two tube lengths, and see which tumbles best.
If it goes wrong
- Slides without tumbling : Cover the slope with felt, foam or a rug.
- Stops halfway : Raise the slope a bit, check the marble rolls freely.
- Marble gets stuck : Remake with thicker paper, or use a smaller marble.
- Falls on its side : Make crisp folds, lighten the decoration.
- One end opens : Add a band of tape around the end.
Safety
- A marble is a choking hazard for under-3s: keep it away from little brothers and sisters.
- The scissor cuts are short and precise: a grown-up can do them.
- Check both ends are firmly closed before playing.