The Question
sander says:
2005-07-19 16:04:28
We all know lightning travels through the path of least resistance.
Let’s say we zoom in on the electricity that’s flowing downwards, and see what it does every 1 nanosecond (it travels about 1 foot in this time period). The flow of electrons gets to a point, and it has to find the path of least resistance to keep going. For simplicity, let’s say it has 1 of 3 options. How does it know which to choose? Clearly, it doesn’t have “senses†to figure this out. If you know your electricity, you know it doesn’t “probe†its different path options until it finds the best way to go. So, how does it know?
A semi-comparable system would be water flowing down a hill. If the water gets to a place where it must choose to go 1 of 3 ways, most of it will go down the steepest path. But some of it will still go down the other two.
Electricity is different. If +10V gets to an intersection, and has to choose between 1 of 3 equally resistive paths (let’s say 250 ohms for the heck of it), one going to +7V, one going to +5V, one going to ground, ALL of the current will go right to ground. Nothing will go down the other two paths. Voltage (potential) difference is just like “steepness†of a hill in this example.
So, how does it know?
Read more