Thunder and Lightning: Nature's Display of Temper
While we no longer attribute the thunder and lightning to the gods of old, the fascination and the fear linger. Lightning is as beautiful as it is deadly. Thousands of people are struck by lightning every year and many of them die.
Nature puts on an amazing display of temper and it can be fun to watch, but understanding the power behind it, and knowing when and where to seek shelter is vital. Without that knowledge, nature's "free" show might "cost" more than you bargained for. It could cost you your life.
A Deadly Force
The Water Cycle
To understand lightning and Thunderstorms, we need to start with the basics, the water cycle. Nature recycles its water through a process of evaporation and condensation.1.The sun heats up the surface water
2.The water evaporates and rises into the air
3.The water vapor cools and condenses forming water droplets, which form the clouds.
4.When the water droplets become heavy enough, gravity pulls them back down again, completing the cycle.
Charge Separation
As the water vapor condenses, it accumulates in the atmosphere as clouds until the droplets are large enough to feel the pull of gravity. Water vapor continues to rise, some water droplets are falling, some are changing phase (condensing) and they are all bumping into each other. With each collision, electrons are knocked off the molecules of water. As the water vapor rises, condenses and freezes, more electrons are knocked off. All the newly freed electrons sink to the bottom of the cloud giving it a negative charge.The disparity in the charges causes an electric field to form. As with the charges, it is negative along the bottom of the cloud and positive along the top. As the collisions continue to knock electron free, the intensity of the electric field increases. It may become so intense that the electron on the earth's surface are repelled. (Opposites attract, like repel) The surface of the earth takes on a positive charge. All the charge needs now is a path. Once strong enough, the electric field will form that path.
Thunder
The quiet rumble of thunder off in the distance will have most people scanning the skies looking for storm clouds. A storm is brewing. Is it moving toward you or away?It wasn't until the 20th century that we truly understood what caused the thunder. It begins with the sudden thermal expansion (expansion due to heat) of the plasma in the lightning channel. For a fraction of a second, the air is superheated, reaching as high as 28,000 degrees Celsius. The superheated air moves faster than the speed of sound in the cooler air causing the shock wave we hear as thunder.
A Beacon Through the Storm
How far away?
We see the flash of lightning, wait a beat, and hear the thunder. Light is electromagnetic radiation and travels at the speed of light. Sound travels much slower than that. You can get a rough estimate of how far away the lightning is by counting the seconds between the flash and the boom. Count the seconds and then divide by three and you will know approximately how far away it is in kilometers. If you want the distance in miles, divide the seconds by five. Too Close!
Thunder is good, thunder is impressive; but it is lightning that does the work.
--Mark Twain
Frighteningly Beautiful
The Lightning Rod
The purpose of the lightning rod is not to "attract" lightning but to offer an easy path to the ground. The long, thin rod was originally developed by Benjamin Franklin in the late 1740's. It's a slender rod, around 2 inches in diameter and has a pointed end. The rod is connected to a thick copper or aluminum wire which in turn is attached to a grid buried in the ground nearby. When struck, the electrical current generated would travel down the wire and be safely dispersed in the ground.Lightning tends to jump around when it strikes. Sometimes it strikes and then jumps around seeking an easier path to the ground. If the strike occurs near a lightning rod, the lightning will jump to it and be dispersed before more damage is done.
Understand the Weather
It's not the tires.
When caught in a storm, staying in your car is the safest bet, but it's not the tires that keep you safe. The metal frame of the car acts like a cage sending the current around and down to the ground. The occupants within the car are usually left unharmed.
Take Precautions
Lightning doesn't always follow a path to the ground. If two parts of a cloud are oppositely charged, the lightning will strike within the cloud. The entire cloud lights up. It is often referred to as sheet lightning. Lightning can arc from one cloud to another as well.The lightning we're the most familiar with is called streak lightning, or forked lightning. It appears to shoot straight down forking just before it strikes. Whatever the name, it is as deadly as it is beautiful.
The safest place to be during a Thunderstorm is in a large building, preferably one equipped with lightning rods. If you are in your car, stay there! It's far better than being out in the open. If you are caught outside, don't stand under a tree. It can act as a lightning rod and you would become part of the conduit. Another consideration is the heat generated by a strike. The boiling sap could cause the tree to explode.
Find a low-lying spot away from the trees or other potential strike zones. Keep your feet together, and hunker down. With your feet apart, discharging current could travel up one leg and down the other. By keeping your feet together, you're not giving it a path to follow. DO NOT lay down on the ground. A discharging flash would travel through your body as readily as it travels through the ground. Keep your head down and wait for the rainbow to appear.
It Won't Last Forever
Are you fascinated by lightning? Do you sit on the porch and watch the storms?
Evelyn_Saenz wrote...
The perfect lens to read on a rainy day.
Lensrolled to It's Raining! It's Pouring!.
Please join us on A Walk in the Woods and add your lens to the appropriate plexo.
Posted April 30, 2009
Tipi wrote...
I love a thunder and lightening storm. It smells so good, fresh! :)) Nice lens, Lizzy!
Posted February 17, 2009
About the Author
Lensmaster ElizabethJeanAllen, aka Lizzy Jean, has been a member since March 16 2008, has rated 3,689 lenses, favorited 454, and has created 169 lenses from scratch. Lizzy Jean donates their royalties to Squidoo Charity Fund. This member's top-ranked page is "The Mallard Duck". See all my lenses
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Resources used to construct this page.
Explore the Weather
Lightning, Museum of Science
Lightning, NASA Primer
Weather Eye, Lightning-Thunder
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