Why do rays travel in a zig-zag instead of in a straight line?

 

It is a wonderful question, which cries out for a clear answer. Let's see if we got it.

Lightning is an electric discharge between two points that are at a sufficient potential difference so that the dielectric medium that separates them (the air) is perforated. When this happens, the electric current encounters an absolutely inhomogeneous medium (the air): regions of greater or lesser density, areas of greater or lesser temperature, slightly different pressures over small distances, more or less humid areas... the electricity tries to reach the opposite potential of the starting point along the path that offers the least resistance, and all this has an influence.

We can make a comparison with falling water: under perfect conditions, a drop of water, looking for the gravitational gradient, falls completely vertical; but if it has other constraints, such as rough terrain, a stream will take the closest possible path to the gradient: it will never run uphill, but it can meanders, curves, bends, shifts of all kinds, etc., which is what rivers do.

It is also what happens with the mineral diffusion between the cracks of the stones as you can see.

#GK