Why does smoke disperse but clouds seem to stick together?

The particles that make up smoke and clouds have important differences, which explains how they appear.

Why do clouds maintain their integrity instead of dispersing uniformly into the atmosphere? - Quora

Why does smoke disperse but clouds seem to stick together?

How long wildfire smoke sticks around in our skies

Why the Wildfire Smoke Makes the Sky Turn Wild Colors - The New York Times

Mushroom cloud - Wikipedia

COVID-19 is awful. Climate change could be worse.

Smoke thunderclouds: Wildfires use the atmosphere to light more wildfires - Bulletin of the Atomic Scientists

Officials warn of dangerous conditions as brush fires bring smoke to D.C. area - The Washington Post

Smoke in Sky - The Impact on Astrophotographers! — Cosgrove's Cosmos