8TH GRADE · CHANGE IN STATE OF AGGREGATION
Evaporation, condensation and humidity
Saturated steam and relative humidity measurement.
The entire theory of the lesson is collected here; you can read it without an account. In interactive mode, the same theory appears as cards, followed by questions. with checking the answer and task, and progress is saved.
Basic Concepts
Saturated steam
Steam is saturated when evaporation and condensation in a closed volume occur at equal rates.
Unsaturated steam allows further preferential evaporation, and the density of saturated steam depends on temperature.
Evaporation and condensation
Evaporation occurs from the surface of the liquid, and condensation turns the vapor back into liquid.
Evaporation is accelerated by heat, wind, and increased surface area; The fastest molecules carry away energy and cool the liquid.
Relative humidity
The ratio of the actual content of water vapor to the saturated one at the same temperature, expressed as a percentage.
Humidity is determined by a psychrometer or electronic sensor; When cooled to the dew point, condensation begins.
Physical quantities
Relative humidity
The fraction of the actual water vapor density from the saturated one.
Unit: dimensionless quantity
Water vapor density
The mass of water vapor per unit volume of air.
Unit: kilogram per cubic meter ·
Saturated vapor density
The maximum equilibrium vapor density at a given temperature.
Unit: kilogram per cubic meter ·
Lesson formulas
Relative humidity
Relative humidity is equal to the ratio of the actual vapor density to the saturated vapor density.
Related formulas
The same formulas in the reference, with symbols and units.
Tasks on the topic
Statements, answer options and the walkthrough.