foam vs Styrofoam

foam and Styrofoam both are nouns.

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

As nouns, Styrofoam is a hyponym of foam; that is, Styrofoam is a word with a more specific, narrower meaning than foam:

foam: a lightweight material in cellular form; made by introducing gas bubbles during manufacture
Styrofoam: a light resilient foam of polystyrene

Other hyponyms of foam include foam rubber.

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

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