Have you ever wondered what lightning is and how it forms? In this lesson, you’ll learn how lightning develops, different types of lightning, and what causes thunder.
What Is Lightning?
We’ve all heard the saying that lightning never strikes the same place twice, but is it true? The answer is absolutely not. In fact, lightning occurs so frequently that it would be hard for that to be true. At any given time, there are 2000 thunderstorms on the planet, and they produce around 6000 lightning strikes every minute. That’s more than 8.5 million strikes a day.
They each have 100,000 times the power of household electricity.So, what is lightning? Lightning is a very quick electrical discharge that occurs between a cloud and the ground, between two clouds, or within a cloud. It can be seen as a bright flash and is followed by the sound of thunder.
How Does Lightning Form?
Lightning is usually associated with thunderstorms, which are short-lived localized storms that have vertical air motion, humidity, and instability. The exact mechanism of electricity developing in a storm is not very well understood. So, lightning is a bit of a mystery. However, there is a series of events that occur for lightning to develop that are known:
- The development of a thunderstorm causes electrical charges to be separated.
- The updraft of air carries positively charged water droplets with it.
- The downdraft of precipitation transports negatively charged water drops downward to the bottom of the cloud.
- The negative charges on the bottom attract positive charges on Earth’s surface directly below the thunderstorm.
- Then, the difference in charges on the bottom of the cloud and on the ground grows stronger and stronger until there must finally be a release.
- A finger of negative electricity shoots down from the cloud and meets a finger of positive electricity that is shooting up from the ground. They connect and a surge of electricity strikes downward.
This may happen several times in rapid succession until all negative charges are gone from the bottom of the cloud. This type of lightning is called cloud-to-ground lightning. It only makes up about 20% of lightning in a storm, but it is the most destructive.There are other types of lightning in a storm. Intra-cloud lightning happens within the same cloud.
The separation of the charges from the top and bottom of the cloud produce lightning between them. Cloud-to-cloud lightning happens in storms in the same way, only the discharge occurs from one cloud to another.Lightning is inevitably followed by thunder.
When a lightning bolt strikes, it causes sudden heating and expansion of the air. This causes a shock wave that becomes a sound wave that we hear as thunder. The lightning and thunder occur at the same time, but to us it seems like the lightning is first. This is because light travels faster than sound.
So, many of us have heard that you can tell how far away a storm is by counting how long it is between when you see the lightning and hear the thunder. This is true. Five seconds in between means the storm is about one mile away.
If you don’t hear any thunder, it means the storm is a dozen or more miles away.
Types of Lightning
There are also many other types of lightning that are not caused by the formation of a thunderstorm, but all are caused by the same basic mechanism as lightning in a thunderstorm. Positive and negative charges are separated and grow in strength until there must be a discharge. They are usually called different things based on where they occur in the atmosphere.For example, St.
Elmo’s fire is a type of lightning. It occurs around ship masts or airplane wings that become negatively charged. If a plane or ship passes through a positively charged cloud, and the charges are strong enough, a discharge of electricity can occur. It appears as a blue glow and has a buzzing sound.
There are also names for types of lightning that occur at very high altitudes: sprites, which look like jellyfish, and blue jets, which look like fountains. Air discharge lightning develops in very dry climates. Lightning can even occur in a volcanic eruption. The different size particles of ash in the eruption accompanied by friction cause positive and negative charges to develop, which can lead to lightning. There are many other types of lightning as well. Some of the most common ones are heat lightning, ball lightning, bead lightning, and forked lightning.
Lightning is a strong and fast discharge of electricity from a storm cloud to the ground, within the cloud, or to another cloud.
Lightning forms due to the separation of electrical charges. As air and moisture rise, positive charges are carried to the top of the storm cloud. As rain begins to fall, it brings negative charges to the bottom of the cloud. That causes positive charges to collect on the ground. The charges build up until flashes of electricity, or lightning, release the tension.The heat of a lightning bolt causes the air to expand releasing a sound wave.
We hear this as thunder. There are many other types of lightning that are not associated with storms, but the mechanism of a separation of positive and negative charges in the atmosphere still cause them. Some of the more common ones are St. Elmo’s fire, air discharge, sprites, heat lightning, and ball lightning.