Comment by pinusc

That's fair to point out. However, I don't think it detracts from the point: the definition is in some sense a detail, because there is a connection between "bubbles forming" and "the temperature water will not rise beyond", but it's subtle and assuming that one equals the other leads to error. The very reason we have that definition is that it's more precise, because in the real world there's details that escape narrow definitions as seen in school or in the kitchen.

As an aside: I love the bubbling patterns of water as it heats, and it's actually a useful skill in the world of tea-making (especially in the gongfu tradition) to estimate the temperature of water based on the amount and size of bubbles. Nowadays I use a temperature-controlled kettle, but in the past I would get by with a clear borosilicate glass kettle and paying attention to the details, which is fun and rewarding in itself—if far less precise.