how does boiling create bubbles which wander from bottom to the top of a liquid?


I know that temperature is given by the movement of the atoms in a substance. But why exactly it happens to form bubbles at the boiling point, which are wandering from the bottom to the top e.g in a pan? If they are made of oxygen , isn’t it at some time depleted? Shouldn’t the water then stop boiling?

In: Chemistry

The bottom of the pan is the hottest place, so the water at the bottom is hottest (and then rises). When it’s hot enough, the water transitions to a gas state – water vapor. Which, as a bubble, rises to the top of your pot.

The bubbles are not “air” in the traditional sense, but instead the liquid near the source of the heat is transformed into a gas and that gas then floats to the top –

The bubbles are steam.
The bottom is the hottest part of the pan. So the water reaches boiling point at the bottom and turns into steam. Its density is way smaller than liquid water so it raises to the top.