MentosCap

This is a cap fitting standard US 1L & 2L plastic soda bottles, meant to hold 4-5 Mentos™ candies to be dropped into bottle to create a rapid CO2 release (e.g., Mentos + Diet Coke soda fountain). It could easily be extended to hold more, but 4-5 was all we needed for the science experiment.

The quick release is operated by sliding a toothpick, coffee straw, nail, or similar through the holes in the side near the base, then stacking the candies (or other payload) onto it. When pulled out (directly or with an attached line) the contents of the chute will fall quickly into the main body of the bottle, since the chute size is almost the exact diameter of the bottle throat (nothing to get caught on).

There are 2 versions of the cap: the straight up "MentosCap" file is an open bore at the top. "MentosCap_Mk.IV" uses an interior parabolic compression to restrict the flow to a much smaller outlet at the top, and has been pre-inverted for easier printing. This requires filling it with