Cars and Lightning
Name: Robyn T.
If you are driving and your car gets hit by lightning
will you be electrocuted? Many people say that the rubber tires will ground the
charge therefore the "safest place" to be during a storm is in your
car. Is this true? Explain!
A car is rather safe in a thunderstorm. However, this is not because the
tires ground you, but rather they serve as an insulation - a more difficult
path for electrons to run. Lightning will take the path of least
electrical resistance. It is likely that that would be a path that didn't
require traveling through the tires.
That being said, lightning is very strange stuff and sometimes
unpredictable. Even though you see a bolt of lightning, you are actually
seeing only the core of the event. The surrounding area is affected as
well. I would think it possible to be affected by a bolt of lightning
striking a tree outside the car in which you are sitting.
What you say about the grounding by wet rubber tires is probably true, I
think that the statement is based on the fact that according to Gauss' Law,
the electric field inside a hollow conducting shell [of any shape] is zero.
So in principle you could even sit safely inside a van de Graff generator
charged to a million volts without fear of electrocution or even a shock.
Notwithstanding, I do not think I would choose to test Gauss's Law, there
some higher order effects!!
Electricity tends to flow through the easiest paths available. Lightning
goes from the clouds to the ground. If it hits your car, the easiest path
is through the metal framework and then through the water on the tires.
Flowing through the air and then through you and the seat is much more
difficult. It relates to electric circuits. Imagine two parallel circuits
attached to a power supply. Let one have a very small resistance (the
framework) and one a very large resistance (air, you, seat). Almost all of
the current will flow through the circuit with the very small resistance.
This same principle applies to lightning rods.
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Update: June 2012