There must be microscopic solid matter, such as dust or salt particles ​ — from thousands to hundreds of thousands of them in each cubic inch [cm] of air — ​ to act as nuclei for droplets to form around.
Selleks peab olema mikroskoopilist tahket ainet, nagu on tolmu - või soolaosakesed — tuhandeid kuni sadu tuhandeid selliseid osakesi õhu igas kuupsentimeetris —, mis oleksid tuumaks, mille ümber võiks moodustuda tilgake.