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b : torrid <a boiling sun>

2: intensely agitated <a boiling sea> <boiling with anger>


Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding environmental pressure. While below the boiling point a liquid evaporates from its surface, at the boiling point vapor bubbles come from the bulk of the liquid. For this to be possible, the vapor pressure must be sufficiently high to win the atmospheric pressure, so that the bubbles can be "inflated". Thus, the difference between evaporation and boiling is "mechanical", rather than thermodynamical. The boiling point is lowered when the pressure of the surrounding atmosphere is reduced, for example by the use of a vacuum pump or at high altitudes. Boiling occurs in three characteristic stages, which are nucleate, transition and film boiling. These stages generally take place from low to high heating surface temperatures, respectively.[1]