We were recently shown a paper by Karen S. Harpp, Alison M. Koleszar, and L. Dennis Geist that presented instructions for the safe demonstration of an explosive volcanic eruption. In less than a second, the explosion carries up to 20 gallons of water into an eruption column more than 10 meters high. Boiling liquid nitrogen encased in a plastic soda bottle provides the driving force for the explosion. The demonstration is appropriate for levels ranging from elementary to graduate school and dramatically illustrates how the rapid expansion of a liquid-hosted gas can cause explosions.
For more information on their cool paper and demonstration visit