Rub the comb with the wool and then place it near the puffed rice. Put some of the rice in the plastic bag. Blow air into the bag and seal it with the tie. Rub the wool over the bag. Now rub both the bag and the comb with the wool.
Static electricity is created when an object gives up or gains electrons.
Rubbing wool over something made of plastic or hard rubber gives that object a positive charge which will attract any object with a lesser charge. The wool gives up electrons to the plastic. You can buy this resource on CD-ROM for use on computers without internet access.