Foam
Part of speech: verb
Definition: To form or emit foam.
Part of speech: noun
Definition: A substance composed of a large collection of bubbles or their solidified remains.
Example sentence: Although we don't know what is outside our universe, astronomers still wonder. Several pictures of what there might be have been dreamed up. An interesting one, called multiverse, has lots of universes. Picture it as a foam of bubbles. Our universe would be one bubble, and we'd be surrounded by lots of other bubbles.
Fizz
Part of speech: noun
Definition: An emission of a rapid stream of bubbles.The sound of such an emission.A carbonated beverage.
Part of speech: verb
Definition: To emit bubbles.To make a rapid bubbling sound.