Lightning is a weather phenomenon that most often occurs during thunderstorms. It can also occur during other weather events that change or alter the atmosphere around them, such as volcanic eruptions.
There are three main types of lightning. The Cloud-to-Ground type is the most familiar due to its appearance, visibility and threat to people, and occurs between a cloud and object on the ground. Cloud-to-Cloud lightning occurs between two unique clouds, and Intra-Cloud lightning occurs within a single cloud.
Facts about Lightning
- Lightning is an electrical discharge between a high amount of electrons at the bottom of a cloud and their resulting attraction of protons in objects in the ground.
- As many as 1 billion volts can be present in a single bolt.
- Thunder can help approximate how far away a lightning strike occurred. For every 5 seconds between a strike and the thunder it caused, the lightning is 1 mile away.
- There are approximately 100 lightning strikes every second on Earth. This equals approximately 8.6 Million strikes per day.
What causes lightning to occur?
The process which causes lightning to occur begins in clouds. Clouds are formed by tremendous numbers of small ice pellets and water droplets. Prior to a thunderstorm, evaporation adds large amounts of water droplets to the atmosphere, and humidity levels are often high. Air currents carry these droplets to the atmosphere where they gather with other water and ice to form enourmous clouds, called Cumulonimbus clouds, that are seen during thunderstorms.
As the evaporated droplets rise and start to condense, they begin colliding with other ice particles already present in the clouds, and electrons are stripped from the particles in the process. The electrons gather near the bottom of the cloud, and the protons move to the top. Through properties of electromagnetism, this enormous charge imbalance causes a similar charge imbalance to take place in the ground and objects below, as protons begin to move upward. Multiple negatively charged paths 'step' down from the cloud. These paths are called step leaders. When the step leaders get close to the ground, ionized paths of protons called streamers shoot out from the ground and objects on the ground to meet the step leaders. When a streamer and step leader meet they form a path for the necessary electrical discharge, or rebalancing. The resulting current between the negatively charged base of the cloud and the positively charged areas in the ground is what we see as lightning. The majority of occurrences of lightning will be followed by occurrences of thunder.
If a thunderstorm or electrical storm is approaching it is important to seek shelter indoors immediately. People should particularly stay far away from trees, telephone and flag poles, open areas such as a field, and most importantly water, but all outdoor locations are unsafe. When lightning strikes one of these objects, the charge has the capability to travel through the ground or water near the area where the strike occurred. If absolutely necessary, automobiles can provide some protection if the entire frame is composed of metal. However, it is not the tires that provide the protection - it is the frame. Moving vehicles that are struck by lightning can become incapacitated and would then be a major potential hazard on busy roadways. For these reasons it is highly advised to cease driving during electrical storms and seek shelter whenever possible.
Inventions that improve Safety
An earlier preparation that is often made to taller stuctures such as highrises and skyscrapers is installation of lightning rods. A lightning rod, sometimes referred to as a Franklin rod or lightning conductor, is constructed of metal. It is connected to a large piece of aluminum or copper wire, which is run into the ground.
Lightning in Literature, Film and Culture
- In the 1985 film 'Back to the Future', Doctor Emmitt Brown connects a wire to the clock tower in downtown Hill Valley to harness gigawatts from a lightning strike in order to send Marty back to 1985.
- In the 1931 film 'Frankenstein', Dr. Frankenstein uses an electrical storm to bring his monster to life. This was unique to the film as Mary Shelley's book "Frankenstein" did not specify how the monster was brought to life.
- In another 80s film, 'The Great Outdoors', a man by the name of Reg had reportedly been struck by lightning 66 times.
- Tampa Bay's professional hockey team (part of the National Hockey League) is known as the Tampa Bay Lightning.
- Bolts are sometimes featured in company logos. The Gatorade logo is one of the more famous to do so.