Why should I squat instead of laying flat on the ground during a thunderstorm?
In: Physics
There’s a pretty good analogy with explosions here. A vacuum sucks air in because the air is less dense inside than outside (at the same temperature). An explosion is similar – a combination of generating a bunch of gas and causing a sudden in temperature results in a large pressure gradient between the origin of the explosion and its surroundings. The surroundings, like a vacuum, suck up the explosion.
The thing that makes an explosion dangerous is that part of you is getting pushed/pulled hard before the rest of you can follow suit, tearing you apart. The more you can mold yourself to the shape of the pressure wave, and the thinner you are, you reduce the pressure gradient so you get accelerated evenly.
A lightning strike is very similar. It dumps a huge amount of charge into a point on the ground. The ground had a relatively even opposite charge before the lightning strike, so parts of the ground that are further away from the lightning strike will suck up the charge from the lightning, causing the lightning’s charge to spread outwards from the point where it struck.
If you have two feet on the ground, there’s a possibility that the lightning strikes in a place where one foot sucks up the charge before the other one can. But instead of you being pushed/pulled unevenly by a pressure wave, the foot that’s further away from the lightning strike may suck up some charge from the foot that’s closer, and it may do so through your body instead of the ground.
That flow of charge is what basically burns you from the inside and overloads the electrical channels that are normally responsible for operating your muscles, including your heart.
Standing on one foot minimizes how much charge one part of your body can suck up before the rest of your body can catch up, minimizing the difference in charge between the most and least charged parts of your body, which in turn limits how much charge flows through you. It also helps limit the path of the charge to just that foot, as those two points are so close together. Squatting is just an easier way to get most of the benefit.
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