foam vs effervesce

foam is a noun but effervesce is not a noun.

Word	Noun	Adjective	Verb	Adverb
foam	Yes	No	Yes	No
effervesce	No	No	Yes	No

As verbs, foam and effervesce are synonyms defined as:

Other synonyms of foam include fizz, form bubbles, froth, sparkle.

foam (noun)	effervesce (noun)
a mass of small bubbles formed in or on a liquid
a lightweight material in cellular form; made by introducing gas bubbles during manufacture

foam (verb)	effervesce (verb)
become bubbly or frothy or foaming	become bubbly or frothy or foaming