LIGHTENING STRIKES

[prateeksikka]

HI THERE ALL!
CAN ANYONE TELL ME WHAT CAUSES LIGHTENING STRIKES IN RAINY WEATHER. I HAVE READ THAT IT IS DUE TO SOME IONS BUT HOW I DONT KNOW.
FROM WHERE DO THESE IONS COME?
::)
PRATEEK

[audioguru]

www.howstuffworks.com  ;D ;D

[prateeksikka]

HI AUDIOGURU!
ANY EXPLANATION FOR THE MECHANISM BY WHICH THE CHARGES SEPARATE?
AS THIS SITE SAYS IT OCCURS DUE TO SEPARATION OF CHARGES.BUT WHY DO THEY SEPARATE AND THAT TOO ONLY WHEN IT RAINS?
  ???

[audioguru]

By majic? ??? ??? ;D

[prateeksikka]

hi my friend!
u cant believe in science and magic together.and u know one thing 90% of magic is made up of scientific tricks.acid turns a litmus paper red. and base turns phenolphthalin pink.magic!!!!!! ;D ;D ;D

[Codyhtml]

i think it is somthing to do about when the clouds get enough water vapor to rain they also have built up + (i think ) charge and the earth is -(i think) so all it is is HUGE arcing of the earth and i've heard that if there was wire longenough to run to one of the sphears in the atmosphere you could short out the earth and the weather would FREAK out :) but that is like 40mi in the sky and so much current would try to flow that it would probably burn the wire up before there was too much damage done :)

[prateeksikka]

yeah that is the case.
it is clear that it is due to separation of charges.but how does water causes these separation.is it possible to generate artificial lightening?
;D ;D ;D

[steven]

when the pressure in the clouds biulds up the exspanding water drops cause an exsplosion and thus lightening is created and on the ground a negative charge biulds up giveing the lightening somewhere to strike if ive got it right

[prateeksikka]

mechanism similar to a photocopying machine!
interesting only diff water in place of ink.
fair enough any comments?
or polar nature of water?
what are clouds made up of?

[Codyhtml]

clouds are made of just water vapor and air :)

[MP]

Prateek,
Thunderstorms are formed when warm air rises quickly from Earth into the sky. As the warm air cools, it forms rain clouds (cumulonimbus). As the warm air continues to rise and cool inside the clouds, it drops water and ice. Lightning is caused by electricity moving in between clouds or between the clouds and the ground. The electricity is formed when the ice and water particles move around rapidly inside the clouds. As the particles move they become oppositely charged and they separate. The positively charged particles go to the top of the cloud and the negatively charged particles sit along the bottom of the cloud. The negative particles along the cloud bottoms grow large and are attracted to the positive charges on the ground. When the "attraction" between the different charges becomes strong enough, electricity flows from the cloud to the ground. This flow of electricity is a lightning strike.
Hope that clears it up for you.

Just as interesting is what makes the thunder: Since the Lightning lasts only a fraction of a second, but it is filled with energy, it is very hot. (It can reach temperatures that are much hotter than the sun). The heat of the lightning is what actually causes the thunder. As the hot electrical charge passes through the air, it rapidly heats up the air. The heated air expands very quickly and makes the loud noise called thunder.

MP

[Guest Alun]

Lightning also produces Xrays and gamma rays that are also present in neuclear radiation: http://news.bbc.co.uk/2/hi/science/nature/2713891.stm

[Dazza]

Nicely explained MP :D.

I'm no expert on the subject That's for sure, except for having the pleasure to witness countless storms here in oz 8) ;D, with spectacular lightning shows :o, anyway to the point I have been led to believe that lightning travels from the ground upwards, and I have heard this being stated many times.  you seem to be very knowledgeable on the subject MP, I would appreciate your thoughts on this ;).

[prateeksikka]

anyway dazza!
u can assume anything whether it flows from clouds to ground or ground to clouds,
+ve in one case -ve in other.
So fast moving air separates the vapours in the clouds and makes them oppositely charged this induces opposide charge on earth(i mean opposite to charge on lower cloud) so charge moves to have neutralization.OK EVERYBODY? ;D ;D

[ante]

Oh, so it’s not AC then?  ;D

[prateeksikka]

no ante!
i dont mean that it is AC.
I mean to say that  u may consider any one of them (the cloud or the ground)
as +ve or -ve ultimately it is the flow of charge which neutralizes the 2.
if we assume opposite, the direction of current is reversed.Now whether +ve neutralizes the -ve or the -ve neutralizes +ve what difference does it make?
nothing. ;D

[MP]

Hi Dazza,
Current always flows from a negative potential to a positive potential. Since the flow is determined by the positive and negative charges, it is flowing to the ground. (Negative particles along the cloud bottoms attracted to the positive charges on the ground.)

MP

[prateeksikka]

hi MP!
WE assume -ve charge on cloud bottom and +ve on the earth.is it merely an assumption i.e can  we assume the reverse?or there is a logic behind it?
:o

[ante]

Hi MP,

That’s correct, from negative to positive because the electrons flow in this direction. British car manufacturers knew this back in the sixties so they connected positive to the chassis (ground). I installed a stereo system in a friends Ford Cortina once and it was some extra work I might add. To be honest this was not wrong thinking just different thinking! ;D

[MP]

Yes, I remember some of those strange Fords with the positive ground. It sure made confusion of a simple task like changing the battery.
  ;D

MP

[ante]

The radio reception was not very good, only the strongest stations worked acceptable. Some time later he found a kind of converter or filter for the antenna wire which made it possible to ground the antenna in the car body to get a good ground plane. I never saw this gizmo so I don’t know what was in it but it worked perfectly. I still wonder how it was solved (changing the polarity of the antenna)? Maybe it’s very simple to solve, it was not expensive. ;D

[Dazza]

The old Volkswagon Beadle, had a positive ground as well.

[prateeksikka]

hi u all!
is there any experiment which can prove that the earth is positive with respect to the lower cloud on a rainy day?
or is it mere a convention?can we actually measure this?
;D

[ante]

Hi prateek,

You will need a high voltage probe for your multimeter and I recommend rubber gloves! ;D
 
I think the polarity of the clouds towards ground (earth) must be considered as a dual power supply. Some are on positive side and others are on the negative side of earth potential. But that’s me thinking and I might be wrong!

Do we have any meteorologist in our community?

[audioguru]

A neon bulb and a very high-value resistor will show you the polarity of static charges fairly safely. I think its negative internal post will light with a negative polarity on it, and it will breakdown at about 90V and prevent any higher voltage from occuring. ;D