A student asked a great question that I am not sure how to answer (or
if my interpretation of first principles are correct).
"If a cloud becomes polarized and induces an opposite charge on the
ground then is the cloud pulled towards the ground? Do charged clouds
float lower?"
An Internet search was not productive nor do I recall reading
anything about this in a text book.
Seems like the answer has to be yes, but clouds are not pulled to the
ground.
A super simplistic calculation of the force between cloud and ground
based on data from the venerable wikipedia source: <http://
en.wikipedia.org/wiki/Lightning#Facts_and_trivia>
assuming cloud and ground charged equal and opposite right before
discharge:
F electric = k(5C)(-5C)/(600m)^2 ~= -600,000 N = -70 tons
Seems non-trival to me even if the mass of the cloud is millions of
tons. Is this force balanced by buoyant forces or is too small to
make a significant difference. To brief due to discharges between
clouds and ground?
Seeking opinions,
Scott
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Scott Goelzer
Physics Teacher
Coe-Brown Northwood Academy
Northwood NH 03261
603-942-5531e218
sgoelzer@coebrownacademy.com
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