Date:2 June 2017
There’s still a lot we don’t know about how to protect a building from a lightning strike.
By Sophie Weiner
It’s hard to believe, but until recently, scientists had never filmed lightning striking a building in high speed. That changed when a team led by physicist Marcelo Saba at Brazil’s National Institute for Space Research caught lightning striking a building in São Paulo, Brazil with cameras filming in 7,000 FPS. The incredible video shows the massive bolt branching before connecting with streamers emitted by lightning rods on top of the buildings, leaving the buildings undamaged. The connection between the lightning and the rod’s streamer causes a brilliant flash that overwhelms the camera.
The lightning strike footage:
This is the first high speed footage captured of a lighting strike hitting a lightning rod, and the lightning rod functioning as intended. There’s a few reasons for this. Cameras need to be positioned close to a building to capture footage like this, making widespread surveillance difficult. The chances of catching footage like this is low, so cameras, filming in high speed, need to be given long observation periods.
Based on the video, Saba’s researchers have published an article in the journal Geophysical Research Letters detailing their findings. These include the speed of the lightning and the streamer emitted by the rod–60 miles per second and .03 miles per second, respectively.
Due to the lack of data, until now, designing lightning rods has involved a lot of guess work. Most of them are modeled to function on very tall buildings, based on work done in labs with long electrical charges. The buildings filmed in this video were under 200 feet tall, giving scientists much-needed observational data in order to understand better how lightning rods function and how to make them better in the future.
Source: Geophysical Research Letters via Gizmodo
This article was originally written for and published by Popular Mechanics USA.