You have in your hands a tube, which you can show to your audience from all sides, and a small ball. You throw the ball into the tube and command it to disappear.
The ball disappears in the cylinder!
You say to the ball, “Appear!” and at once the ball drops out of the tube.
Then you take a shoelace and tie a loose knot.
Lower the knot into the tube.
Now pull the knot out of the tube–and it is now untied!
The secret to this magic trick is in the unusual tube, although to the casual viewer the tube looks very ordinary. To make the tube you will need a piece of heavy cardstock with a hole cut in the middle and two pieces of self adhesive felt.
Stick the first piece of felt onto the paper as shown.
Bend the cardstock and felt into a tube so that the two edges of the felt come together.
You should now have a slit in the felt like this.
Spread glue on the cardstock and attach the second piece of felt, which is a bit wider than the first. Make sure the edge of the felt lines up with the inner felt piece.
Finish gluing the felt to the tube. Now you have a tube with a hidden slit that only you know about.
Now you can confidently show the tube to your audience.
While showing the magic trick, inconspicuously slip the thumb of one hand through the slit. First you stop the ball from falling through the tube. Then, putting your thumb into the knot, you cause it to come untied as you pull it out of the tube. You have more magical abilities than you thought!