Getting drenched in a thunderstorm might seem like the epitome of a bad day, but research suggests it can be a lifesaver when lightning strikes.
In what looks to be a strong contender for a Ig Nobel Prize, researchers subjected 3D models of a human head to the equivalent of a direct lightning bolt, revealing that they suffer less damage when wet.
“If you’re outside and there’s no shelter, wet skin is better than dry skin because the water film is like a ‘protective layer,'” said René Machts, first author of the study from the Ilmenau University of Technology in Germany. But, he added, “It’s safer to find a ‘sheltered’ place and make yourself as small as possible.”
Writing in the journal Scientific Reports, Machts and colleagues say theoretical studies have previously suggested that wet skin can reduce the magnitude of the current that passes through the human body when struck by lightning. In addition, research has represented animals with wet skin have a higher survival rate when exposed to lightning.
However, it remained unclear how water on a human head – as can occur in the rain that often accompanies thunderstorms – could affect the impact of a lightning strike.
To delve into the issue, the team built two human head models made from three layers of a agar-like substance containing varying levels of sodium chloride, carbon black or graphite to reflect the conductive properties of the brain, skull and scalp.
They then attached electrodes to the different layers, and the platform on which the models were placed. While one of the models was left dry, the other was sprayed with a solution representing rainwater. Each model was then placed in a chamber and exposed to 10 simulations of a direct lightning strike.
The results show that a current moved across the “scalp” with each lightning strike for both model heads, an event known as a flash. However, shortly after the strike, but before the skip, the wet head had a 12.5% lower average electrical current in the brain layer and a 32.5% lower specific energy in the brain compartment than the dry head – something they may say behind the increased survival rate among wet animals in earlier experiments.
The team adds that the wet head also showed fewer signs of damage, such as perforations of the scalp or cracks, after lightning. But, they say, further work is needed.
Machts said: “Based on these results, we plan to create further head models to investigate the effect of [for example] headgear and can examine materials for an optimal headgear to further reduce the current in the head. It can certainly help hikers who can’t find shelter.”
