You're never supposed to use a hairdryer in the bathtub because the electric shock could kill you. So what happens to fish when lightning strikes? Why don't thunderstorms routinely kill off every animal in the sea?
A Bolt to the Blue
There are a few reasons, but here's the most basic: Lightning just doesn't strike the ocean that much. In 2014, the Journal of Geophysical Research published a map that amassed five years of global lightning-strike data from two weather satellites. It showed that lightning strikes over land 10 times more often than it does over oceans.
According to the NASA Earth Observatory, this makes sense because of the way lightning forms. Solid earth absorbs sunlight and heats up faster than water does. That heat causes more convection and instability in the atmosphere, which in turn causes more lightning-producing storms to form.
Even still, lightning does strike the water sometimes. Why doesn't that kill fish by the thousands? Physics has the answer. Like metal, water is a good conductor, so it encourages the electrical current to travel over its surface rather than delve underneath, the same way a Faraday cage protects its contents from harmful shocks. If a fish surfaces at the wrong moment, it can certainly be hit by lightning. Luckily, most fish spend the majority of their time underwater. People don't, however, which is why you should immediately get out of the water if a storm is approaching.
This article first appeared on Curiosity.com.