Lightning Science and Safety

Did you know that Benjamin Franklin conducted his famous experiment in which he flew a kite during a thunderstorm during this week in 1752? Benjamin Franklin was looking to demonstrate the connection between lightning and electricity. In fact, we know today that lightning is a discharge of static electricity from the atmosphere. Lightning can strike from cloud-to-cloud, cloud-to-ground, and even intra-cloud (inside one cloud) discharges can occur. Let’s look back into history to see how this experiment worked…

Courtesy: Franklin Institute.

Ben Franklin and his son built a kite and attached a metal wire to it to act as what we call today a ‘lightning rod’. To the string Franklin attached a metal key, and he and his son launched the kite. From under a shelter, they were able to observe electricity travelling through the kite, to the key, and collected the charge in a Leyden jar, an antique device capable of storing electric charge. The results of his experiment led to the development of the lightning rod, a device used even today.

So, what exactly is a lightning rod?

Lightning is essentially a giant spark of static electricity that discharges from a thunderstorm, similar to the discharge we can observe after walking across a carpet and touching a metal doorknob. However, lightning strikes carry immense amounts of electricity, and the column of air around a lightning bolt can become hotter than the surface of the sun (this results in a shock wave emanating out from the strike, which we hear as thunder!).
Simply put, a lightning rod is a sharp metal object which is attached to the roof of a building. The rod is connected to a conductive wire which is buried in the ground. The purpose of this device is to create a low-resistance pathway to the ground should lightning strike the building. By carrying the current easily into the ground, the safety of people inside the building is ensured and electrical and heat damage (as a result of the strike itself or a resulting fire) to the building is prevented. Lightning is one of the most frequently encountered weather hazards, and fire departments across the United States respond to thousands of calls per year due to lightning strikes.

The Insurance Information Institute reports there were over 109,000 claims submitted to homeowners insurance companies for lightning-related damage, with a value totalling over 825 million dollars. While the most claims were filed in Florida and Texas, where there are many thunderstorms, lightning damage and injuries occur in every state. Just this week, a motorcyclist on a Florida highway died as a result of a direct lightning strike to his helmet.

Did you know that June 23-29 is National Lightning Safety Week? The National Lightning Safety Council (NLSC) website has many resources to help you prepare for various activities during which you may encounter lightning. The NLSC reports (graphics shown below) that most lightning fatalities occur as people are doing leisure activities, outside enjoying the summer weather. Further, while there are a large variety of activities during which lightning fatalities can occur, many happen while people are involved in water-related activities.

Here are some safety tips to keep you and your family safe during thunderstorms during this busy summer season:

  • Remember that NO place outside is safe if thunderstorms are in the area: WHEN THUNDER ROARS, GO INDOORS!
  • Immediately move to a safe shelter if you hear thunder. The best options are sturdy buildings or an enclosed vehicle. Stay inside for at least 30 minutes after you hear the last thunder.
  • Indoors, stay off corded phones, avoid windows, sinks, baths and faucets; stay off porches.
  • If you are caught outside with no safe shelter, reduce your risk by making yourself as low as possible: get off hills and elevated areas, stay away from trees, get out of water bodies, and stay away from conductive objects such as fences. Squat low and minimize your contact with the ground by staying on the balls of your feet if possible.

For more information, as well as real time forecasts, visit the National Weather Service website.

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