If you’ve ever been close enough to lightning when it strikes you may be familiar with the startling high frequency thunderclap or crack it makes. But the high frequency soundwaves of the clap are attenuated by their travel through the air away from the source so that from a kilometre or so away all you hear is the growling of the thunder rumbling away as it clatters and rebounds off everywhere it hits.

I learned about this from Randall Munroe’s fun book How to: Absurd scientific advice for common real-world problems.

Thunderclap or rumble

Caused by ash and rock interacting inside a cloud instead of ice particles. As you can imagine you can get this with volcanoes which can be pretty spectacular. Here’s more about how lightning forms inside a thunder cloud, the regular kind.

Sketchplanations tagged with lightning