Science Experiment: Make a Diet Coke+Mentos Rocket

Step 4: Set the bottle of Diet Coke down on the ground, or have somebody hold it. Now, carefully slide the strip of tape with the Mentos attached down into the mouth of the bottle and into the air space. (Be careful to keep the Mentos from coming into contact with Diet Coke just yet — or it will spurt right away and you'll get soaked!)