Experiment Procedure:
Gather materials: 1 two liter bottle of Diet Coke (otherwise unflavored for best results), 1 package of at least ten mint Mentos, 12 cm of dental floss (or other string), a 5 cm (at least) thick piece of plywood, a 5cm roofing nail, a 4mm and 8mm drill bit, a power drill and two or three meter sticks. Step 1: Using the roofing nail, score ten Mentos by slightly applying pressure to the middle of the Mentos candy. Create a depression in the candy so that the drill bit will not slip off the Mentos when drilling. Do this for all ten candies. Step 2: Set up your drilling station by laying the plywood down. Ready your ten scored Mentos and begin to drill through them. Start by applying slight pressure downward on the candy while slowly drilling and only slightly increasing the drilling speed once the hard sugar coating is broken though. The speed increase after the coating, is necessary because the inside of the candy is gummy and a faster speed is needed to work through it. The candy might crack in half, do not use these because they could break apart during the experiment and cause a premature eruption. Repeat this process for all ten Mentos. Step 3: Drill the desired design in the bottle caps. It is better to collect other bottle caps and drill those because if the caps are removed from the test bottles, the carbonation in the soda will escape. Drill the desired designs in both diameters but on separate caps so that the height will vary. Remember that fewer holes in the caps create a greater concentration and therefore create the best results. Step 4: String your Mentos on the dental floss. Once you have completed that, take the string and thread it through one of the central holes in the drilled bottle caps. Step 5: Stand the three meter sticks end to end, vertically. Secure them as you see fit (duct tape is the best). Attach them to the Diet Coke bottle in the same fashion so that they will record the height of the eruption. Step 6: Open your test bottle and quickly remove enough soda so that when you screw on the drilled cap, holding the string of Mentos, the soda will not touch the candy resulting in a premature eruption. Once the drilled cap is securely on, hold the string of Mentos vertically and make sure it will not get stuck anywhere on the cap when it is released. Step 7: Before letting go of your sting, have a partner stand nearby to take pictures of the eruptions because this is a more accurate method of recording the eruption height. Step 8: Release your string and run!
(Repeat the procedure as many times as you wish, try varying the number of Mentos to achieve different heights.)
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