Why is it that birds are able to stand/sit on electrical power lines whereas if we were to try this, we would be electrocuted?
Asked by: Tochi Ugbor
Actually, if we were to sit on a power line and not touch anything else like the birds do, we would not get electrocuted! The reason for this has to do with the fact that current, a flow of electrons, flows along a path of least resistance. The electrons want to get to where they are going in the easiest possible way, much like a person might walk on the sidewalk instead of the grass because it is easier. When a bird sits on a wire and the electrons reach the part of the wire where the bird is sitting, the electrons have two options. They could go through the bird's feet and encounter a large amount of resistance or they could go through the metal. All metals are conductors which means that electrons flow through them easily. Because it is easier to travel through the metal instead, the electrons don't go through the birds feet, so the bird stays safe.
The same thing would happen if a person sat on a wire and the electrons would go through the wire instead of through the person. If, however, the person reached out to a tree or anything else connected with the ground, there is a new path of lower resistance and the electrons would go through the person to the ground, electrocuting him.
Answered by: Evan Weinberg, Physics Student, Hawken School
'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '