What is lightning?
Lightning is a form of electrical discharge between clouds or between a cloud and the ground. The discharge may take place between two parts of the same cloud, between two clouds, or between a cloud and the ground. Lightning may appear as a jagged streak, a flash in the sky, or in the rarer form of a brilliant ball. Thunder is the sound waves produced by the explosive heating of the air in the lightning channel during the return. Lightning Specifics • Most lightning strikes occur either at the beginning or end of a storm. • The average lightning strike is six miles long. • Lightning reaches 50,000 degrees Fahrenheit, fours times as hot as the sun’s surface. • A cloud-to-ground lightning channel can be 2 to 10 miles long. • Voltage in a cloud-to-ground strike is 100 million to 1 billion volts.
Much of the following was taken or adapted from NOAA Technical Memorandum ERL NSSL -102 by Holle and Lopez. Lightning is a transient discharge of static electricity that serves to re-establish electrostatic equilibrium within a storm environment. Any pilot will tell you that the average thunderstorm has a very turbulent environment. Strong updrafts and down drafts occur with regularity, even within small thunderstorms. The updrafts transport water droplets up into the cloud, while ice particles descend from the frozen upper regions of the cloud. As they do, they bump and collide with each other. Through this process, electrons shear off of the ascending water droplets and collect on the descending ice particles. (A similar effect occurs when you rub your feet across a carpet before touching a door knob.) This generates an electric field within the cloud, with the top having a positive charge, and the bottom having a negative charge. An electric field is also generated between the botto
How it works: Electrical charges develop inside a storm cloud. Positively charged atoms go to the top of the cloud. Negatively charged atoms go to the bottom. If the negatively charged atoms become too crowded, they “jump” to another part of the cloud, to a different cloud, or to the ground. This jump causes a huge spark of static electricity called LIGHTNING! ~~Warning ~~ DURING A LIGHTNING STORM, seek shelter in a house or large building. Stay away from windows and metal objects, such as radiators.
Lightning, as best we understand, is a channel of negative charge, called a stepped leader that zigzags downward in roughly 50-yard segments in a forked pattern. This step leader is invisible to the human eye, and shoots to the ground in less time than it takes to blink. As it nears the ground, the negatively charged step leader is attracted to a channel of positive charge reaching up, a streamer, normally through something tall, such as a tree, house, or telephone pole. When the oppositely-charged leader and streamer connect, a powerful electrical current begins flowing. A return stroke of bright luminosity travels about 60,000 miles per second back towards the cloud. A flash consists of one or perhaps as many as 20 return strokes. We see flicker when the process rapidly repeats itself several times along the same path. The actual diameter of a lightning channel is one-to-two inches.
Lightning is a bright flash of electricity produced by a thunderstorm. All thunderstorms produce lightning and are very dangerous. If you hear the sound of thunder, then you are in danger from lightning. Lightning kills and injures more people each year than hurricanes or tornadoes; between 75 to 100 people. What causes lightning? Lightning is an electric current. Within a thundercloud way up in the sky, many small bits of ice (frozen raindrops) bump into each other as they move around in the air. All of those collisions create an electric charge. After a while, the whole cloud fills up with electrical charges. The positive charges or protons form at the top of the cloud and the negative charges or electrons form at the bottom of the cloud. Since opposites attract, that causes a positive charge to build up on the ground beneath the cloud. The grounds electrical charge concentrates around anything that sticks up, such as mountains, people, or single trees. The charge coming up from thes