Science Experiment: Make a Diet Coke+Mentos Rocket

Step 3: Cut a 3-inch piece of duct tape and lay it on a flat surface, with the sticky side up. Then open a roll of Mentos and take a half-dozen of them out. Make a line of Mentos that sticks to the tape. You can fold the tape over a bit to keep the candy in place, but make sure that most of the surfaces of the candy pieces are exposed.