Adult supervision required

Setup

1. Tie a double knot in the short rope and hide it in your pocket.
2. Tie a single knot in the long rope around the tube.
3. Slide one end of the long rope through the tube and move the knot to the tube's end. Pull the rope to make the knot disappear.

Perform

1. Pretend to sprinkle "magic dust" from your pocket. Secretly hold the knotted rope while doing this.
2. Pull the long rope through the tube to show the knot is gone.
3. Shake the tube and let the hidden knotted rope fall from your hand.