Lightning is an electric current that passes between two clouds, within a single cloud, and between the cloud and the earth. Lightning strikes are common during thunderstorms. They can travel large distances and follow a zig-zag path.
What Is Lightning?
Lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground. In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground.
When the opposite charges build up enough, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning.
The flash of lightning temporarily equalizes the charged regions in the atmosphere until the opposite charges build up again.
Lightning can occur between opposite charges within the thunderstorm cloud (intra-cloud lightning) or between opposite charges in the cloud and on the ground (cloud-to-ground lightning).
Lightning is one of the oldest observed natural phenomena on Earth. It can be seen in volcanic eruptions, extremely intense forest fires, surface nuclear detonations, heavy snowstorms, in large hurricanes, and obviously, thunderstorms.
How Lightning Forms
Lightning is a giant spark of electricity in the atmosphere or between the atmosphere and the ground. In the initial stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground; however, when the differences in charges become too great, this insulating capacity of the air breaks down, and there is a rapid discharge of electricity that we know as lightning.
Lightning can occur between opposite charges within the thunderstorm cloud (Intra Cloud Lightning) or between opposite charges in the cloud and on the ground (Cloud-To-Ground Lightning). Cloud-to-ground lightning is divided into two different flashes depending on the charge in the cloud where the lightning originates.
What Creates The Bright Light In The Clouds During Lightning?
The atmosphere usually acts as an insulator and doesn’t allow the lightning to flow anywhere else except within the cloud. This limits the electric charges, along with the light produced by them, within the boundaries of the cloud, illuminating the entire cloud.
How Does Lightning Work To Strike The Earth?
When the charges developed in the cloud are strong enough, they may break the insulating property of the atmosphere and make electric current flow down to the earth that has a positive charge, which travels back to the sky as a brighter spark.
Usually, the positive charge on the ground develops on tall structures such as buildings, trees, electricity poles, etc. The downward and upward flows of electric current are cumulatively seen as lightning.
What Makes The Loud Sound Along With Lightning?
Loud Sound or Thunder is created when lightning passes through the air. The lightning discharge heats the air rapidly and causes it to expand. The temperature of the air in the lightning channel may reach as high as 50,000 degrees Fahrenheit, 5 times hotter than the surface of the sun. Immediately after the flash, the air cools and contracts quickly. This rapid expansion and contraction creates the sound wave that we hear as thunder.
The loud thunder that follows the lightning bolt is commonly said to come from the bolt itself. However, the grumbles and growls we hear in thunderstorms actually come from the rapid expansion of the air surrounding the lightning bolt.
As lightning connects to the ground from the clouds, a second stroke of lightning will return from the ground to the clouds, following the same channel as the first strike.
The heat from the electricity of this return stroke raises the temperature of the surrounding air to around 27,000 C° (48,632 F°). The rapid rise in temperature creates a rapid increase in the air pressure as well, rising to 10 to 100 times the normal atmospheric pressure.
Under such pressure, the heated air explodes outward from the channel, compressing the surrounding air. As the heated air expands, the pressure drops, the air cools, and it contracts. The result is a shock wave, with a loud, booming burst of noise sent in every direction.
Because electricity follows the shortest route, most lightning bolts are close to vertical. The shock waves nearer to the ground reach your ear first, followed by the crashing of the shock waves from higher up.
Vertical lightning is often heard in one long rumble. However, if a lightning bolt is forked, the sounds change. The shock waves from the different forks of lightning bounce off each other, and the low-hanging clouds and nearby hills create a series of lower, continuous grumbles of thunder.
Lightning may cause death or severe injury if it strikes a person. Hence, it is important to take adequate safety precautions during lightning. Stay away from electrical appliances, open doors, and windows, water bodies, and open fields, and remain indoors.
Where Does Lightning Strike?
Most, if not all, lightning flashes produced by storms start inside the cloud. If a lightning flash is going to strike the ground, a channel develops downward toward the surface.
When it gets less than roughly a hundred yards of the ground, objects like trees and bushes and buildings start sending up sparks to meet it.
When one of the sparks connects the downward developing channel, a huge electric current surge rapidly down the channel to the object that produced the spark.
Tall objects such as trees and skyscrapers are more likely than the surrounding ground to produce one of the connecting sparks and so are more likely to be struck by lightning.
Mountains also make good targets. However, this does not always mean tall objects will be struck. Lightning can strike the ground in an open field even if the tree line is close by.