A classic ‘classroom experiment’ viewed in slow-motion could have interesting implications for the use of ex equipment in the presence of alkali metals.
The explosion of sodium in water is a common demonstration worldwide, and has an equally common explanation – the release of explosive hydrogen gas.
But new research suggests something else drives the explosion of the metal, and Pavel Jungwirth of the Academy of Sciences of the Czech Republic has published his and his colleagues’ findings in the academic journal Nature.
They explain that when the metal reacts with the water, hydrogen gas is formed – and this occurs because electrons leave the surface of the metal.
However, they point out that electrons are negatively charged, leaving behind an unstable positively charged surface.
At slowed-down speeds, it is possible to see the repulsive force of this positive charge driving spikes out of the metal’s surface, increasing its surface area – something anyone with experience of explosions will know is a precursor to detonation.
The findings could be a step towards more detailed understanding of other hazardous materials too, and as detonation mechanisms become more closely understood, the design and use of ex equipment can also continue to become ever more sophisticated.
