When the tape is pulled off the table top the breaking chemical bonds almost always give the tape a strong static charge. For the second part of the set, stick one pice onto the table and then stick the second stripe to the back of the first. Pull the two off the table together and THEN separate the two stripes. The stripes will invariably be oppositely charged. To show the tape is charged bring it near a few small scrapes of paper.
Induction is a process by which a charge can be given to a metal .
The process is difficult for some students to see. When the rubbed balloon is brought near a metal, the positive charges on the neutral metal are attracted to the near side and the negative charges are repelled to the far side. Polarization is a process by which a charge can be effected on the surface of an insulator. A rubbed balloon sticks to a wall by the process of polarization of the molecules in the material of the wall. Many molecules have one end that is slightly more positive and the other end slightly more negative.