LIGHTNING

this article that i am posting is about lightning, an atmospheric electrical phenomenon.

what is lightning?

Lightning is an atmospheric discharge of electricity that is usually accompanied by thunder. This usually happens during thunderstorms, and sometimes during volcanic eruptions or dust storms.In the process of atmospheric electrical discharge, a bolt of lightning can travel at speeds of 60000 m/s and can reach temperatures approaching 30000 °C . There are approximately 16 million lightning storms in the world every year. Lightning can also occur within the ash clouds produced by volcanic eruptions or can be caused by severe forest fires that generate enough dust to create a static charge. Ice inside a cloud is known to be a key element in lightning development, and may possibly cause a forcible separation of the positive and negative charges within the cloud. This will then result in the formation of lightning. Lightning is an electrostatic discharge that occurs between the cloud and the ground, the cloud and other clouds or merely within a cloud.


a bolt of lightning is created when ...

opposite charges within the cloud attract one another. As the positive and negative areas grow more distinct within the cloud, an electric field is created between the oppositely-charged thunderstorm base and its top. The further apart these regions are, the stronger the electric field and and this will result in stonger attraction between the charges. However, the atmosphere is a good insulator of electicity. thus, a large amount of charge has to build up before the strength of the electrical field overpowers the atmosphere's insulating properties. A current of electricity forces a path through the air until it encounters something that makes a good connection. The current is discharged as a stroke of lightning.While all this is happening inside the storm, beneath the storm, positive charge begins to pool within the surface of the earth. This positive charge will shadow the storm wherever it goes, and is responsible for cloud-to-ground lightning. However, the electric field within the storm is much stronger than the one between the storm base and the earth 's surface, so about 75-80% of lightning occurs within the storm cloud.





this video shows a lightning stom that occured in HongKong , may 2003.



this video shows lightning striking Toronto CN tower.


Adrienna:D

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