Also to know is, why does my boiling water foam?
When you throw them into boiling water, a heated and moist environment, the starch continues to absorb more and more water until it bursts. The result is starch molecules being expelled into the water, creating the froth you see.
Beside this, does Salt prevent water from boiling over?
There are also a few commonly touted tips that won't actually keep your pasta from boiling over, or that shouldn't be used to keep the pasta from boiling over. However, salt won't make the water stop frothing; it also doesn't make the water boil faster (unless you add an unpalatable amount of it!) Add oil to the water.
Air bubbles usually get into water from the mains when there's a problem nearby like a burst mains pipe, and it can also be caused by a faulty plumbing fitting. The air is dissolved under pressure and released as millions of tiny bubbles when the tap is run giving the water that frothy appearance.