The candy-cola soda geyser experiment, at different altitudes

Source: Science Daily

Dropping Mentos® candies into a bottle of soda causes a foamy jet to erupt. Although science fair exhibitors can tell you that this geyser results from rapid degassing of the beverage induced by the candies, the precise means by which bubbles form hasn’t been well characterized. Now, researchers have used experiments in the lab and at various altitudes to probe the mechanism of bubble nucleation.