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Vapor Pressure

Vapor Pressure

Vapor Pressure Chart
Introduction: To some, it is conventional wisdom that attempting to cook something in water at a higher altitude than sea level will take longer than at sea level and that cooking something in water at lower altitude than sea level will take longer than at sea level. This phenomenon can be explained by a concept known as vapor pressure, or the pressure of a vapor in contact with its solid or liquid form. Pressure can be defined as the force acting over a given area.

The reason that cooking times differ depending on altitude relates to the fact that the vapor pressure is equal to the external pressure, as well as to the concept of boiling point. Boiling point, aside from being known as the temperature at which boiling occurs, also refers to the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid, leading to the liquid being changed into a vapor. Generally, at higher altitudes, the pressure tends to be lower than at sea level, leading to lower boiling points than at sea level and a higher cooking time overall. Conversely, at lower altitudes, the pressure tends to be higher than at sea level, leading to a higher boiling point than at sea level and a lower cooking time overall.


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