What is Boiling point?
[[File:Dominica boiling lake.jpg|thumb|A boiling lake in [[Dominica]]]] The '''boiling point''' of a [[substance]] is the [[temperature]] at which the substance boils, or enters a state of rapid [[evaporation]]. For pure [[water]] this is 100° [[Celsius]] or 212° [[Fahrenheit]], at [[Standard temperature and pressure|standard pressure]]. Standard pressure is 1.0 [[Atmosphere (unit)]]. Boiling points can be changed in several ways. The addition of [[solute]]s or other substances usually changes the boiling point. Additionally, changing the [[pressure]] on a liquid changes its boiling point. The boiling point of a liquid depends on the [[pressure]] of the surrounding air. An increase in air pressure raises the boiling point; a decrease in air pressure lowers the boiling point. In the low pressure environment at the top of Mt Everest for example, water boils at only 69 °C (156.2 °F). [[Aquanaut]]s find that water in their habitat only boils at high pressure. Boiling point can also be defined in terms of [[vapour pressure]] as the temperature at which vapour pressure of liquid becomes equal to atmospheric pressure. [[Sugar]], [[salt]] or other non-volatile [[solute]]s in water will usually make the boiling point higher. [[Alcohol]], in contrast, is a volatile chemical that lowers the boiling point of water. Even a large amount dissolved in the water will usually make only small changes in the boiling point. {{physics-stub}} {{States of matter}} [[Category:Thermodynamics]] [[Category:Basic physics ideas]]