Showing posts with label Lightning. Show all posts
Showing posts with label Lightning. Show all posts

Friday, 18 May 2007

Lightning? Get Wet!

I know its incredible, but that's the truth. And its not me who's saying, but some really knowledgeable people on Discovery.

Yesterday, at the usual dinner table fight over the remote with my mother (my father prefers to fix his attention on the food only), it was I who came out trumps (quite surprisingly). So instead of Virrudh, it was now Drama on Discovery. The subject of the show, as I understood, was lightning and its probable effect on a human being (unfortunately I had already missed the first 30 minutes of this incomparable show). Anyway, something is always better than nothing. The 'Drama' revolved around a person (Ah! forgot the guy's name) who was a victim of a thunder strike. And the thing of wonder was that this guy survived! But certainly with huge handicaps. He now walks with a limp, and lives with a severely affected nervous system. The magnitude of the devastation wrought on his nerves was so much that, as an experiment revealed, he could not feel electric shocks of 400 volts whereas a normal human being will jump out of his chair at 30!!

And so, the mission of the team was to find out how he survived, maybe with severe disabilities, but still the guy survived. How? The answer to this question proved to be quite elusive as several hypothesises failed to provide any satisfactory solution. At last, a professor of physics (a bald guy with a Russian name), provided the theory that would ultimately solve the mystery. He elucidated that when lightning falls on the body an extraordinary phenomenon takes place known as 'flashover'. Flashover is an unintended high voltage electric discharge over or around an insulator, or arcing or sparking between two or more adjacent conductors. In layman's language it means that most of the lightning falling on your head is disbursed around you by being conducted to the ground by the skin, leaving only 1%, which goes right through your body. Now even that 1% comes to be around 5 Amperes, which is more than enough to kill you right on the spot. Then how did the guy survive? Surely not just due to 'flashover'.

At the time when the cruel lightning struck it was raining cats & dogs, and he was literally dripping, soaked completely in water top to bottom. And this is what precisely saved him! As further experiments in the University of Manchester proved, 'flashover' is greatly facilitated by water, which makes the skin a better conductor. Thus most of the current flows outside the body and only the tiniest part actually enters the body (well, even that 'tiniest' part isn't that tiny after all). So friends, if it's lightning and you are in the open, make sure that you get wet first!

PS: These shows make TV something more than just an 'idiot box'.

Again PS: I found this link while surfing on the net. This is about a man, Roy Sullivan, who was struck by lightning an incredible 7 times, but managed to survive each time!!!
http://en.wikipedia.org/wiki/Roy_Sullivan

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