Science Guide for Kids: All About Lightning

by: David Miller


Have you ever wondered how lightning is created? Do you know that there are actually different types or forms of lightning? Did you know that people see lightning differently depending on where they are viewing it? The purpose of this guide is to answer these questions regarding lightning and provide you with basic lightning facts and information. Lightning is a fascinating subject with many aspects to learn about.

What is Lightning and How Does it Form?

Simply put lightning is an electric current. It often stems from thunderstorms, but can also come from other things as well. You can sometimes see lightning in a volcanic eruption, a surface nuclear detonation, an extremely heavy snowstorm, a very big hurricane or an exceptionally intense forest fire. Every thunderstorm produces lightning. Inside a thundercloud you will find many small ice particles or bits bumping into each other as they swirl through the air. Each bump or collision creates an electric charge. Eventually the entire cloud is full of electrical charges and the positive and negative charges separate. The positively charged ice crystals form at the top of the thundercloud while the negatively charged ice crystals drop to the bottom of the cloud. Huge charge differences develop. Beneath the cloud a positive charge will build up on the ground due to the attraction of opposites. Tall objects (such as trees, mountains, telephone poles or even people) can be a possibility for positively charged particles to rise up from the ground. When the charge climbing these points eventually meets with a charge reaching down from the thunderclouds, you have a lightning strike.

What are Different Types of Lightning?

When you think of lightning do you picture bolts with many branches or possibly an entire cloud lighting up? Both of these examples are considered different types or forms of lightning. Many types of lightning exist. The following are some of the more commonly discussed types of lightning.

Cloud-to-Ground: Cloud-to-ground is considered the most dangerous form of lightning. These lightning strikes usually stem from the negatively charged base of the cloud and travel down to the positively charged ground. The lightning bolts may strike tall objects such as buildings or trees and can cause fire.

Intra-Cloud: Intra-cloud lightning is the most common of the lightning forms. The lightning is caused by two opposing charges connecting within the same cloud. Observers of this type of lightning will typically only see a flicker or a bright flash of light. The cloud is actually masking the flash and making it difficult for people to see. Occasionally a portion of the flash will leave the cloud and will appear as a bright channel of light or a flash.

Intercloud: In order to have intercloud lightning occur you need at least two clouds. This is a less common form of lightning. The positive charges in one cloud connect to the negative charges in another cloud. The lightning strike travels through the air from one cloud to another.

Forked Lightning: Jagged lines of lightning with visible branches are considered forked lightning. They can travel from the clouds to the ground, between two clouds, or shoot from a cloud into the air.

Sheet Lightning: When a flash of light completely lights up a cloud it is referred to as sheet lightning.

Heat Lightning: Heat lightning is actually when the lighting flashes are so far away that you cannot hear the thunder. It is called heat lightning because it often occurs on hot days in the summer when the sky appears to be clear.

Ball Lightning: This type of lightning looks like a glowing ball floating through the air. It is a rare form of lightning which can be seen in a variety of colors (or even change color). Usually it is red, orange or yellow. It is often the size of a grapefruit but can be considerably larger or smaller.

Ribbon Lightning: When a bolt of lightening separates due to wind and appears as parallel lightning streaks it is called ribbon lightning.

Chain or Bead Lightning: When a lightening bolt is broken into dotted lines while fading it is referred to as chain or bead lightning.

High-Altitude Lightning: This type of lightning appears high above thunderclouds as various brightly colored light flashes. You typically cannot see these flashes from the ground because the clouds obstruct your view. Red sprites, blue jets and green elves are part of this lightning form and are named according to their typical color. Red sprites are large but weak lightning flashes that often occur in clusters. They tend to be shaped like long cylinders. Blue jets stem from the center of a thunderstorm and are cone-shaped flashes. They tend to be brighter than red sprites. They usually fan outward and then disappear. The green elves are shaped like a saucer or a doughnut.

St. Elmo's Fire: This form of lightning appears above pointed objects located on the ground and can be seen as a greenish or bluish glow. It is created by small positively charged sparks reaching up to negative charges that are either in the air or are in clouds that are above the ground. They can sometimes be seen right before a lightning strike when a thunderstorm is near.

Anvil Lightning: This type of lightning is often referred to as "the bolt from the blue" because it often appears suddenly from a seemingly cloudless sky. A bolt at the top of a thunderstorm arcs away from the main cloud and strikes the ground where the skies above often appear clear.

Words Associated With Lightning

Do you know what a proton or an electron is? Do you know what a leader is when it relates to lightning? There are many, many words that can be associated with lightning in some manner. This guide will define for you some of the more common lightning-related words.

Arc: A big electric current that surges through the air and is seen as a very bright, hot light. The current goes through a channel consisting of ionized air just like lightning.

Branches: When parts of a stepped leader are not part of the main channel and are illuminated, they are considered branches. They are not quite as bright as the main channel.

Channel: The ionized (charged) air path on which a discharge flows. It lights up (illuminates) during discharge.

Discharge: The discharge is where charge differences between two opposite charges are equalized by a current flow down a charged channel.

Electrons: When particles have a negative charge they are referred to as electrons.

Flash: A discharge of lightning.

Fulgurite: When lightning strikes sandy soil, the glassy and brittle formations that can be produced are called fulgurite. The strike of lightning heats up the soil and fuses the soil particles together that are around the channel path. A tube-like and hollow formation results which is shaped just like the section of lightning that formed it.

Ionization: Air becomes conductive through the process of ionization. It is caused by a very large charge difference between two areas composed of opposite charges.

Leader: When there are too many electrons in a thundercloud they can form a channel of charged air called a leader. It stems from the cloud and reaches for the ground while seeking positive charges. A stepped leader moves in steps and branches out along the way. A leader can also move continuously in a single path.

Lightning Rod or Lightning Protection System: The purpose of a lightning rod is to provide a safe path for the current from the lightning to flow through. It intercepts a lightning strike and directs it safely to the ground avoiding damage to objects such as buildings and boats.

Protons: When particles have a positive charge they are considered protons.

Return Stroke: When an electrical charge flows from the ground to a thundercloud you have a return stroke. A huge amount of energy and thunder are released by a return stroke which is very bright.

Sferics: A lightning discharge can produce radio waves which are called sferics.

Streamers: Protons on the ground create a channel of charged air that reaches from the ground toward the sky searching for a leader to connect with.

Lightning Safety Tips

The saying "When thunder roars, go indoors" is a very important one because there is no safe place outdoors when a thunderstorm hits. There are a few things you can do to reduce your risk of injury when outdoors, but getting inside a safe building or vehicle is best. Lightning can be very beautiful but it is very dangerous as well. In the United States, lightning is a leading weather-related cause of injury and death. If you're outdoors and seeking shelter, standing under a tree is one of the most dangerous places to be. Ten percent of people who are struck by lightning die. Seventy percent of people struck by lightning suffer long-term effects such as memory loss, permanent brain damage, personality changes or severe burns. Following safety tips will help to reduce your risk of injury from lightning.

• If you hear thunder seek a safe building or vehicle. A safe building is fully enclosed and has a roof, walls and floor as well as wiring or plumbing. Examples include homes, schools or churches.
• When you are inside a safe building stay away from water. Avoid showers, sinks and bath tubs. Remember water conducts electricity.
• When indoors stay away from electrical equipment such as computers. Do not use appliances during a storm or telephones with cords.
• Stay away from windows and doors when you are inside during a storm.
• Safe vehicles are considered fully enclosed vehicles with metal tops. Examples include minivans, buses and trucks. When inside the vehicle do not use radio communications during a storm.
• If you are driving a vehicle during a storm slow down and proceed with caution. If there is a safe area for you to pull off the road do so.
• Do not leave your vehicle during a thunderstorm.
• Remain inside until 30 minutes after you hear the last sound of thunder.
• If you are outside and there is no shelter stay far away from trees and crouch down.
• If you are outside with other people and there is no shelter stay at least 15 feet away from each other.
• Avoid water areas such as lakes (and even puddles) when outside during a storm.
• Also avoid anything with metal when you are outside during a storm.

Lightning Experiments and Activities

Many experiments and activities have been created in order to learn more about lightning. Here are links to some activities and experiments that are both fun and educational.

• Make Lightning! With this experiment you will see the formation of lightning.
• Listening to Lightning: All you need for this experiment is thunder and your ears.
• Static Electricity: Enchanted Learning offers some static electricity experiments as well as discusses lightning and electrons.

If you are loving learning about lightning, then check out the following links for more great information on the subject.

• Lightning by Weather Wiz Kids
• Arizona State University and Lightning
• National Lightning Safety Institute
• Lightning!
• Lightning Free Games and Activities
• Lightning by Porter Johnson of IIT
• Types of Lightning
• Lightning, Step by Step
• Lightning From Academic Kids
• Lightning