effervescency
Ef`fer*ves"cence, Ef`fer*ves"cen*cy, n. Etym: [Cf. F. effervescence.] Defn: A kind of natural ebullition; that commotion of a fluid which takes place when some part of the mass flies off in a gaseous form, producing innumerable small bubbles; as, the effervescence of a carbonate with citric acid.