boiling bubbles

[rogers.jen]

why does boiling water bubble?

[Jules001]

It is to do with the particles in the liquid matter. As they are heated they gain kinetic energy and bounce around which is why you see the bubbles and the liquid moving and bouncing off the side of the container.

[nightmare]

jules001
What ??? no explanation given there at all.

First, as the water heats up, dissolved gases come out of solution and appear as bubbles on the base of the container.
Once the water reaches boiling point, it begins to change to its gaseous state - water vapour (not steam -steam is partially condensed). This will occur first at any irregularities on the container surface, giving rise to rapidly expanding bubbles. Hence, the water starts to boil and bubble.

[Clanad]

Since boiling occurs when the vapor pressure inside the bubble(s) equals atmospheric pressure one finds that if the atmospheric pressure is less that standard (such as on a mountain top) the boiling will still occur, but at a much lower applied temperature. Therefore, hardboiled eggs or making coffee while camping here in the Rocky Mountains of western U.S., takes a lot longer than usual...

[Panic Button]

I used to work as air cabin crew and had to boil eggs to order for breakfast in first class.

It was a nightmare getting them right, as water boils at less than 100 degrees at altitude. The cabin pressure is equivalent to that on an 8000 foot mountain.