https://archive.md/oDREv
"Benjamin Franklin invented lightning rods in the 18th century, and the devices
have been protecting buildings and people from the destructive forces of
lightning ever since. But the details of how lightning rods function are still
the subject of scientific research.
Although modern lightning protection systems involve extra equipment that makes
them more efficient, the lightning rod itself is quite simple: a copper or
aluminum rod set above the highest point of a building, with wires connected to
the ground. When lightning strikes a building it will preferably pass through
the rod — the path of least resistance — and then through the wires into the
ground, protecting the building and its contents from the extremely high
currents and voltages produced by lightning.
But a rod doesn’t wait for the lightning to strike. Less than one millisecond
before the lightning touches it, the rod, provoked by the presence of the
negative discharge of the lightning, sends a positive discharge up to connect
to it.
Brazilian researchers recently got lucky, photographing this event with
high-speed video cameras at very high resolution. They captured the electric
action in São José dos Campos, a city northeast of São Paulo.
The scientists were in the right place, at the right time, and with the right
equipment to capture 31 of these upward discharges as they happened. With their
location, about 150 yards away from the lightning strikes, and their camera, a
device that records 40,000 images a second, they were able to take clear
photographs and a slow-motion video of what happens in that instant before the
charge from the rod meets the charge from the lightning bolt. The scientists’
study and photos were published in
Geophysical Research Letters in December."
Via
Future Crunch:
<
https://futurecrunch.com/good-news-river-restoration-malaria-kenya-teen-pregnancy-new-zealand/>
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
