Background

There is some debate as to the reason for why CO2 rapidly comes out of solution when a Mentos is added to Diet Coke.  Below are links to two explanations.  Our investigation involved determining the rate of the "reaction": CO2 (aq) ---> CO2 (g).  

Some Explanations::

Nucleation:  Mythbusters video explanation

Surface Tension and Nucleation: General Chemistry online website

Surface Tension: Lee Marck 


The debate rages on...

Procedure

Two liter bottles of Diet Coke were brought to different temperatures by placing the bottles into water in a bucket.  The rate of gas escaping the bottle was measured two ways.  First a Vernier Stream Flow sensor was placed at the mouth of the bottle and a single mentos was added to the Diet Coke.  Flow Rate data is shown below.  Second, trials were run and the flow rate determined using the video analysis features of Vernier Logger Pro.  The raw video is linked below.

Our Mentos + Coke Videos

[=Awesomeness]

Mentos + Diet Coke

 

Warm Trial  (34 °C)