Dave H sure is angry today!!

[Sierraman]

"gym gravity" <[email protected]> wrote in message
news:[email protected]...
> Sierraman wrote:
>
> > I saw a documentary once that rubber tires on a car were a factor
because
> > they are not grounded, but I think the biggest factor was the metal
shell
> > which dissipates the lightning more evenly like a trailer shell that is
also
> > grounded. I think you need a dedicated ground of at least 6 feet in the
> > ground to be effective.
> >
>
> The film of sweat coating your body acts in the same way the metal shell
> of a car does. Most of the 'lectricity travels in the water on the
> surface of your skin. The problem is, it causes the water to boil so
> quickly that the force of the steam escaping tears your clothing off.
> When they find you, you'll be naked. (And covered in burns from the
> boiling sweat.)

What a way to go! :-(

 

[gym gravity]

Sierraman wrote:
>Computers now a days are also dangerous as phone lines are usually
connected to them.

not mine!

 

[gwhite]

Robert Chung wrote:
>
> Ewoud Dronkert wrote:
> > If the lightning can make it down from the sky to you, it can sure make
> > it from you to the ground.
>
> Lightning goes up.
> http://www.mmem.spschools.org/grade5science/weather/lightning2.html

The pre-condition is severe electrical stress between ground and the cloud,
there is no "bias" in that respect. The air (dielectric) is denser at lower
altitude, so it seems reasonable that this portion will begin to break down
first. However, in terms of integrated "charge flow" for a given strike, that
may not mean that the net flow is from ground to the cloud.

I believe I recall that clouds can have charge of either negative or positive
(lightning can go from cloud to cloud too, again IIRC). If it is negative, then
the net charge flow will be from cloud down, because the mass of the stripped
off electrons is so much less than the mass of positive ions. But the process
of stripping off electrons and sending them "down" would begin at the "bottom,"
since that is where breakdown begins. If the cloud is positive, then net charge
flow is "upwards."

I do not believe the distinction of up/down makes an important practical
difference. Once the air begins to break down it is over -- it doesn't really
matter where it started if the path includes the earth. The earth is an
infinite reservoir (similar to the idea of a heat reservoir in thermodynamics)
than can either sink or source electrons.