Lightning – Facts and Fiction


For millennia, humans have been fascinated by lightning. Ancients couldn’t identify this natural phenomenon, thus they deified it. Many cultures have a god of thunder (Zeus, Thor, Indra and Tlaloc to name a few), and in most of these cases, lightning is considered a symbol of anger of god. People knew the destructing power of lightning, but did not know how and why it happened. Nowadays, lightning is a well understood occurrence (thanks to scientists like Benjamin Franklin), yet some myths still prevail. We aim to disperse these myths.

Lightning happens when two opposite electronically charged regions come closer, and they neutralize themselves. This is done by a rapid exchange of charges, with voltages as high as one billion volts, releasing as much energy as ten billion Jules. This is enough energy to light a 100W bulb for 10 years! The problem in harvesting this energy is, it comes as a rapid discharge, rather than a steady flow. Imagine you are given 1 billion rupees, how awesome would that be? Now imagine that amount in coins, and that coin bag being tossed from a 10 storied building. Would you catch it, or would you run for your life?

Sometimes, lightning occur between two clouds, or even between two regions of the same cloud. However, what interests us is lightning occurring between clouds and ground. These are not that rare, with around 100 of them striking earth every second. Around 2000 people are killed worldwide every year by lightning. Nobody would survive a direct lightning strike. But there are few things you can do to protect yourself.

 Thor - Norse god of Lightning
When lightning occur, seek refuge inside a building or a vehicle. If you cannot find such a place, find a place far from tall structures and water bodies (such as lakes), and stay crouched to make you as short as possible. But do not lie down, as the current from a lightning can travel through ground, and can electrocute you. If you are inside a building, avoid using electrical equipment plugged to an outlet, such as televisions and land phones. Some people believe mobile phones attract lightning. This is a myth. You are safe to use mobile phones, as long as it is not plugged to a wall outlet, and you are avoiding other risk factors (such as being near a tall tree). You should also avoid showering and washing dishes (anything involving running water), as water can conduct electricity.

To protect your building from lightning, you can install a lightning rod on your building. This is a tall antenna, with three pointed prongs on top. This would attract lightning, and would safely conduct them underground. Some people believe lightning rods throw lightning at nearby buildings, and therefor oppose installing lightning rods on nearby buildings. This is also a myth. The area of lightning rod’s protection is defined in few ways, but is usually considered as a 45 degree cone from top of the rod. Also, many electrical lines nowadays use something called “Surge Arrestors”, which act like lightning traps. These would divert the charge from any lightning hitting the electricity lines to earth.

Protection zone of a Lightning rod
Another characteristic of lightning is the thunder. Many people do not fear the lightning, but fear the thunder. This is also a myth. Thunder cannot hurt you (unless it is so loud that it would cause you hearing loss). Thunder occurs due to rapid increase of temperature and pressure accompanied with lightning. In fact, you can find the distance to a lightning using the thunder. Let us see how. We know light and sound travel at different speeds in air. Light travels almost instantly, and sound travels at around 350 meters per second. Since both of these occur at the same place and same time, and lightning appear instantly, we can find the distance by calculating how long it takes the thunder to reach us. For example, say thunder takes 3 seconds after lightning. Then the thunder has traveled 350 * 3 = 1050 m or around 1 Km. Now that some myths have been dispelled, and some safety tips been dispersed, it is time to put aside the fear of lightning, and to marvel at this beautiful natural phenomenon.

Post a Comment

0 Comments