A 9/11 documentary showed up in my YouTube recommendations so I decided to watch it. As I was doing so, I realized that there were no shock waves when the planes hit the towers. You can hear the sound of the explosion travelling, but no massive window smashing/shattering like in the Oklahoma bombing or the Beirut explosion or even the [Black Tom explosion](https://en.wikipedia.org/wiki/Black_Tom_explosion#Explosion).
Why weren’t windows in New York blown out en masse that day? Was it due to the nature of the explosion? Thank you in advance!
In: Physics
Explosions can be either subsonic (no shockwave) or supersonic (shockwave). Subsonic explosions are most commonly associated with slower reactions called deflagration. Gasoline igniting in an engine is an example of deflagration. Supersonic explosions are usually created through detonation, which are reactions that are so energetic they occur faster than the speed of sound, generating a shockwave.
The combustion of jet fuel would have been deflagration, creating a subsonic explosion, but no shockwave.
Latest Answers