To make a rocket our of Mentos and diet coke, you are going to need a 2 liter of diet coke, three Mentos, a screw, and a magnet. First, thread all three Mentos on the screw and set aside. Next, open up the bottle of coke. Take the head of the screw and place it inside the bottle cap. After that, put the magnet on top of the cap to hold the screw in place. Now very carefully, screw the cap onto the bottle making sure not to prematurely drop the Mentos in. After the cap is secure, remove the magnet and watch the show!