The Mentos geyser became an Internet/YouTube phenom some time ago. Theories abound on the chemistry of the phenomenon. It seems the surface roughness and gum arabic of the Mentos are the critical elements.
If you've been living off-world for the past couple of years, take a moment to familiarize yourself with the Mentos geyser.
In the meantime, I developed a demonstration narrative to examine the physics of the Mentos geyser. Not the chemistry. Just the physics.
To examine the physics, measure the mass of the geyser ingredients before and after the eruption. This will allow you to calculate the mass of the fizz ejected in the eruption.
Measure the maximum height of the eruption and the length of the interval during which the eruption occurred. Doing so will allow calculations of the mass flow rate, the speed of the fizz as it erupts, and ultimately the power developed in the eruption.
The error bars on these calculations are significant. Estimations and simplifications dominate. But the fundamentals are there.
Where does this demo fit into the physics curriculum? I'm planning on using it at the end of my unit on energy.
Anyway, here's the sheet. Keep in mind this is version 1.0 of the sheet. I'm open to suggestions on how to improve it.
If you're looking for a slick way to get the Mentos into the soda without getting the soda onto you, check out the Geyser Tube from Steve Spangler Science.