system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does every granade, missle, and atomic bomb's cloud always form a mushroom shape in particular? Why not any other shape?
gpt
There's a lot going on in an explosion,  I'll try to keep it simple. 

Heat rises,  there's more heat at the center of a destination than at the edges, so the heat in the center rises faster than elsewhere. That starts the formation,  when the heat rises more, it starts to cool and spread out, forming the top of the mushroom. 

Then debris and material that had been lifted by the explosion begin to fall, curling the sides of the cloud downwards.  

There's also some rotational motion from the temperature differential in the cloud,  which helps it maintain its shape longer than it normally would.