is boiling water a continuous phenomenon?
for instance, based on pressure you can usually assume that ~100c is enough to boil it - but surely it must partly happen at 90c also? this is all statistics at the infinitesimal small scale right? or is the phase switch boundary REQUIRING a 100c @ sea level pressure

my understanding is, as water boils from 0->100, steam is still produced even before it reaches 100c for some particles, just out of managing to break the water boundary - but it may also be that as the whole pot is warming up to 100c, some areas will reach 100c earlier (base) and those phase change.

thoughts?