what does it mean when something has potential difference?

Question

i know it means that the voltages are different, but i dont really get it. A bird can stand on a wire thats has really high voltages and not get shocked because it has potential difference. what does that mean? does the bird has the same voltage as the wires?

Answer 1

Look at it this way.
Like hydroelectricity.
Water that is higher has a higher potential.
Water on the floor cannot spin a turbine, but water on your roof can spin a turbine on the way down to the floor.
There is a gravitational "potential" there.
The bird does not get shocked because if he sits on the
wire he is at the same potential.
Like you can stand on top of a tall building and not get killed.
But if the bird gets shorted to ground, or connected to the negative wire, then he will get fried because current flows through the path, just like if you step off the building you will flow in the gravity down to ground and splat.

So the potential is a "potential" to do work, and the current is the actual flow.

Answer 2

Electrostatic potential defference means that electrons on one side (the low side) have more energy than the electrons on the other side (the high side). It's like a hill. The ball at the top of the hill has more energy, which turns into kinetic energy if the ball rolls down. The funny thing with current is that because of convention, we say that current flows in the direction that the positive charge would move, opposite the flowing electrons. So current flows from high to low.

So in order for current to flow, it has to flow from an area of high potential to one of lower potential. The current sink has to be big enough to absorb all of the current flowing into it without its voltage changing.

So the bird on the wire absorbs a little bit of charge from the wire and quickly assumes the same potential as the wire (without getting cooked). There's no substantial flow of current.

Now if you had a very large bird that could simultaneously touch a high voltage wire and a ground wire (or the ground), that would be a different story. The ground can absorb as much current as you like, so current will rapidly flow through the bird from the high voltage to the low (ground). The bird will get cooked in the process.

So feel free to touch high-voltage wires only if (like the bird), you are well isolated from ground. And no, rubber soles, won't cut it for high voltage.

Answer 3

yes, the bird is at the same positive potential as the wire but no current is flowing through the bird because the bird is not grounded. if the bird somehow became grounded while sitting on the wire the current would flow through the bird to ground and he would be fried. Like a squirrel walking on a wire. If the squirrel brushes up against the ground wire on the pole when he gets off the wire he gets it. when linemen are working on high voltage mega watt power transmission lines they have a metal rod with a hook on it they attach to the line to put themselves and their bucket at the same potential as the transmission line. as long as something doesn't become grounded they are safe.

Answer 4

It simply means that the object has an over abundance of electrons or a lack of electrons in relation to the ground or another object.

All electrical potential must complete a circuit in order for current to flow. If the poor bird in your example sitting on a high voltage line were to put one of his feet on the ground he would be pretty much vaporized and cooked to a crisp as the current instantly shot through him to ground!