The nature of the specific liquid-vapour system gives rise to two types of boiling: "Pool boiling" and "Flow boiling". The change of phase from liquid to vapour across a liquid-vapour interface is called evaporation. Pool boiling is also of interest from the perspective of understanding the boiling phenomenon. Although a number of investigators have observed different regions of pool boiling heat transfer, S. Nukiyama conducted a systematic study on pool boiling over electrically heated nichrome and platinum wires and presented a boiling curve. The intense evaporation under the bubble leads to periodic dry patches on the heater surface that are rewetted by the surrounding liquid, resulting in a reduction in the slope of the boiling curve. Nucleate Boiling with Mixtures Nucleate boiling of mixtures of two liquids with different boiling points results in the preferential evaporation of the more volatile component at the evaporating liquidvapor interface.