How does lightning form?
Lightning; one of nature’s most awesome, beautiful, and deadliest phenomena. Lightning is an electric current caused by a static discharge. In a thunderstorm, raindrops and frozen bits of water make contact and rub against each other and soon the clouds are filled with electric charges. It’s very similar to a person shuffling across the room in bare feet and touching a metal door knob. A tiny lightning bolt jumps from hand to door knob.
Negative charges form at the bottom of clouds and positive charges accumulate at the top of clouds. Like charges repel each other. Negative and negative charges repel. Positive and positive charges repel.
The ground beneath a cloud will become positively charged because the negative charges in the ground under the cloud are driven away or repelled by the negatively charged cloud. The term for this event is called “charging by induction”.
Now we have “negative” cloud sitting above a “positive” ground. Unlike charges attract.
Charge concentrates or builds up on anything that is sticking up, such as a tree, mountain, fishing pole, or person.
A tiny leader charge goes up from these sharpened points, and a huge charge comes down from the cloud and that is the bright lightning flash that we see. The average lightning bolt carries 30,000 amperes of current. In comparison, a typical toaster uses 10 amps. The air is heated to over 50,000 degrees Fahrenheit. The color varies from clear white to yellow orange.
Thunder is not the angels in heaven clapping and applauding, as our Mother told us kids. Thunder is the shock wave created by heating the air. The light flash we see travels at the speed of light, or 186,000 miles a second, almost instantaneously. The sound from lightning, or thunder, moves 1,100 feet a second. Light moves about a million times faster than sound. It takes sound five seconds to travel a mile. You want to know how far away the lightning is from you? Count the time between flash and thunder and divide by five to get the distance in miles.
Thunder is often heard as a rolling, slowly dissipating rumble. The sound from various portions of the long stroke reach the ear at slightly different times.
Cloud to cloud lightning is of little concern. Although a few planes have been disabled by lightning and crashed, modern aircraft are equipped with static discharge wicks that drain the charge and prevent radio interference and also drain the charge. Aircraft are frequently struck by lightning with no ill effects. Charges reside on the outside of a conductor and airplanes are very good conductors.
Obviously it is the cloud to ground lightning that is the most dangerous. Cattle under trees are killed, forest fires are started, and buildings are damaged.
In the summertime, we often see lightning on the horizon, but we not hear the thunder. We kids on the farm called it heat lightning or sheet lightning. It really is lightning from a distant thunderstorm that can be as much as 100 miles away. The lightning, aided by the refraction or bending or light in the atmosphere, can be seen from a great distance. But the thunder from that lightning travels 10 or 15 miles, at best.
Periodically we would see a tree that had been struck by lightning. The lighting strike heats the sap in the tree to steam, and the resulting explosion bursts parts of the tree into many splinters. Well, isn’t there some little sap in every family tree?
Lightning kills about 30 people every year in the United States. Most of the deaths are caused by people doing outdoor recreational activities such as fishing, camping, and playing golf. One of the safest places to be is inside a metal car or inside your house, away from the window.
Lightning is not strictly an Earth event. Lightning has been observed on Venus, Jupiter, and Saturn.