Thunder and lightning: a sound and light show
Thunderstorms are terrifying and yet beautiful to watch. Featuring lightning as well as thunder, they are one of nature’s most common weather phenomena. In fact, the earth is struck by lightning almost 100 times per second! Thunderstorms are created in the giant cumulonimbus clouds found in the sky on hot summer days. The show they put on is hard to top! The amount of electrical energy produced in a storm can set houses and forests on fire, cause electrical blackouts, and damage airplanes. Traveling through electrical wiring, lightning can also damage computers. Very humid tropical regions are most often hit by thunderstorms. The Indonesian city of Bogor, in the South Pacific, holds the record. In 1916, storms occurred for 322 days, that is, about six days a week!
How lightning is formed
The winds found in a cumulonimbus cloud create a disturbance inside it. Rain droplets and ice crystals in the cloud begin to rub together and crash into one another, creating tiny electrical particles. These particles, charged with either a positive or a negative current, are attracted to one another. This attraction between opposite charges causes the particles to move toward one another, creating lightning. The following illustration shows how lightning moves between a cloud and the ground. A single bolt of lightning may produce enough current to run 8,000 toasters all at the same time!
1- Positive charges collect near the top of the thundercloud, while negative charges collect near the base. Positive charges gather on the ground below the cloud.
2- The negative charges in the cloud are attracted to the positive charges on the ground. As they move toward one another, they create invisible sparks.
3- When the two invisible sparks meet, they create a path that makes the positive charges travel from the ground up to the cloud. This upward movement creates a visible lightning bolt.
What is thunder?
When lightning crosses the sky, it makes the air around it so hot that it produces a powerful explosion. This sudden movement of air around the lightning bolt creates a loud sound: thunder!
When lightning strikes!
When a thunderstorm hits, it is important to take shelter immediately, either in a building or in a vehicle with closed windows. The power of the electricity released by the lightning is strong enough to cause severe injuries, even death. In spite of the danger, it’s surprising to know that four out of every five people struck by lightning actually survive!
Also see:
In the Visual Dictionary:
- "meteorology" section
In the encyclopedic capsules:
- The phenomenon of the seasons
- Winter storms: a world of snow and ice
- Cyclones, monsters of the ocean
- Land meteorological station
In the ikonet games:
- Put it in its place!: tropical cyclone
- Put it in its place!: winter precipitations
