When you’re boiling a pot of water, right before the water starts to boil if you watch carefully at the bottom of the pot there will be tiny bubbles that form and disappear. Why do they just disappear instead of floating up to the top once they’re already formed??

Question

When you’re boiling a pot of water, right before the water starts to boil if you watch carefully at the bottom of the pot there will be tiny bubbles that form and disappear. Why do they just disappear instead of floating up to the top once they’re already formed??

In: Physics

Answer 1

To further expand, there’s different ‘regimes’ of boiling. As the bottom surface is heated above the boiling point, we don’t actually see any bubbles until the surface is a few degrees past boiling. The larger the temperature difference, the more bubbles we see form and eventually make it to the top. This is what we refer to as nucleate boiling.

If the temperature of the surface gets too high, a stable vapor film actually forms over the surface and traps the bubbles.
This is referred to as film boiling.

[Boiling curve](https://www.engineersedge.com/heat_transfer/water_boiling_graph_curve_13825.htm)