To start, we need the supplies; Baking Soda, Vinegar, Mint Mentos, and Diet Coke.
Next, we started with the Diet Coke and Mentos. Using a 16 0z bottle of Diet Coke, and dropping one mento into it. (You may want to do this someplace where it wont make a mess; bathtub, sink, etc).
The eruption turned out to be fast and not very large.
Now onto the Vinegar and Baking Soda. We filled a beaker with four tablespoons of baking soda, and 1/4 cups of vinegar. The eruption was more like a shookin-up bottle of soda. It didn't last more than 15 seconds, and was even smaller than the first experimet with Diet Coke and Mentos.
To conclude, the Diet Coke and Mentos had the larger eruption, even beside the fact that it is not a chemical reaction.