Submission + - Driving Force Behind Alkali Metal Explosions Discovered (nature.com)
Kunedog writes: Years ago, Dr. Philip E. Mason (aka Thunderf00t on Youtube) found it puzzling that the supposedly "well-understood" explosive reaction of a lump of sodium (an alkali metal) dropped in water could happen at all, given such a limited contact area on which the reaction could take place. And indeed, sometimes an explosion did fail to reliably occur, the lump of metal instead fizzing around the water's surface on a pocket of hydrogen produced by the (slower than explosive) reaction, thus inhibiting any faster reaction of the alkali metal with the water. Mason's best hypothesis was that the (sometimes) explosive reactions must be triggered by a Coulomb explosion, which could result when sodium cations (positive ions) are produced from the reaction and expel each other further into the water.
This theory is now supported by photographic and mathematical evidence, published in the journal Nature Chemistry. In a laboratory at Braunschweig University of Technology in Germany, Mason and other chemists used a high-speed camera to capture the critical moment that makes an explosion inevitable: a liquid drop of sodium-potassium alloy shooting spikes into the water, dramatically increasing the reactive interface. They also developed a computer simulation to model this event, showing it is best explained by a Coulomb explosion.
The Youtube video chronicles the evolution the experimental apparatuses underwent over time, pursuant to keeping the explosions safe, contained, reliable, and visible.
This theory is now supported by photographic and mathematical evidence, published in the journal Nature Chemistry. In a laboratory at Braunschweig University of Technology in Germany, Mason and other chemists used a high-speed camera to capture the critical moment that makes an explosion inevitable: a liquid drop of sodium-potassium alloy shooting spikes into the water, dramatically increasing the reactive interface. They also developed a computer simulation to model this event, showing it is best explained by a Coulomb explosion.
The Youtube video chronicles the evolution the experimental apparatuses underwent over time, pursuant to keeping the explosions safe, contained, reliable, and visible.
