What is Lightning?
What is Lightning?
Lightning is the visible discharge of static electricity within a cloud, between clouds, or between the earth and clouds.
Scientists still do not fully understand what causes lightning, however most experts believe that different kinds of ice interact in a cloud. Updrafts in the clouds separate charges so that positive charges move up to the top of the clouds, while negative flow to the bottom. When the negative charge moves down, a “pilot leader” forms. This leader rushes toward the earth in 50 meter discrete steps, ionizing a path in the air. ‘The final breakdown generally occurs to a high object, the major part of the lightning discharge current is then carried in the return stroke which flows along the ionized path.
Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions in the atmosphere or ground temporarily equalize themselves, causing the instantaneous release of as much as one billion joules of energy. This discharge may produce a wide range of electromagnetic radiation, from very hot plasma created by the rapid movement of electrons to brilliant flashes of visible light in the form of black-body radiation. Lightning is often followed by thunder, an audible sound caused by the shock wave which develops as gases in the vicinity of the discharge experience a sudden increase in pressure. It occurs commonly during thunderstorms and other types of energetic weather systems.
The three main kinds of lightning are distinguished by where they occur: either inside a single thundercloud, between two different clouds, or between a cloud and the ground. Many other observational variants are recognized, including "heat lightning", which can be seen from a great distance but not heard; dry lightning, which can cause forest fires; and ball lightning, which is rarely observed scientifically.
Humans have deified lightning for millennia, and lightning-inspired expressions like "Bolt from the blue", "Lightning never strikes twice (in the same place)" and "blitzkrieg" are in common usage. In some languages, the notion of "Love at first sight" literally translates as "lightning strike".
A Lightning Protection System provides a means by which this discharge may enter or leave earth, without passing through and damaging non-conducting parts of a structure.
A lightning protection system does not prevent lightning from striking; it provides a means for controlling it, and preventing damage by providing a low resistance path for the discharge of energy. Apart from the devastation that a Lightning strike causes, it is absolutely unpredictable.
Like all Acts of God, it causes Billions in losses annually. But unlike other natural occurrences, we can successfully and economically protect ourselves against the onslaught of nature.
How does lightning form?
Lightning is an electric current. To make this electric current, first you need a cloud.
When the ground is hot, it heats the air above it. This warm air rises. As the air rises, water vapour cools and forms a cloud. When air continues to rise, the cloud gets bigger and bigger. In the tops of the clouds, temperature is below freezing and the water vapour turns into ice.
Now, the cloud becomes a thundercloud. Lots of small bits of ice bump into each other as they move around. All these collisions cause a build up of electrical charge.
Eventually, the whole cloud fills up with electrical charges. Lighter, positively charged particles form at the top of the cloud. Heavier, negatively charged particles sink to the bottom of the cloud.
When the positive and negative charges grow large enough, a giant spark - lightning - occurs between the two charges within the cloud. This is like a static electricity sparks you see, but much bigger.