Relative humidity: What do students know about it?

The concepts of evaporation and precipitation as related to relative humidity have evolved from a mechanistic paradigm (air and water particles showing macroscopic characteristics), to a saturation paradigm (water vapor dissolving in air up to a maximum value; air showing saturation capacity), to the correct kinetic model (evaporation and condensation as a dynamic equilibrium, Dalton's law of partial pressure, Bernoulli's Kinetic theory of gases). Unfortunately, most of the nomenclature on relative humidity, evaporation, condensation, and precipitation was coined during the saturation paradigm period and persists, even though more correct terminology exists (equilibrium vapor pressure instead of saturation point, for instance).

The incorrect concept of saturation with respect to relative humidity is very pervasive. Unlike other science misconceptions that are acquired by people through their daily experiences, their own environment explorations, their social interactions, and media, this misconception is also formally taught. Regardless of its origin, scientific misconceptions are tenacious and very resistant to change, mostly because unlearning is extremely difficult if the information "makes sense" from an uninformed or simplistic viewpoint. Because no research has tried to determine the extent of misconceptions about relative humidity, this study aims to contribute to the science education literature in this important area.

The purpose of this paper is to investigate college students' knowledge of the concept of relative humidity by (1) documenting current student ideas about relative humidity, (2) detecting what misconceptions students have about relative humidity and related areas such as evaporation, condensation, and precipitation, and (3) providing evidence that the questionnaire used for data collection is valid and reliable. The research design included the use of a locally-designed, multiple-choice survey to collect information on students' concepts of relative humidity, evaporation, condensation, and precipitation before the topic is covered in class. The participants were enrolled at OU's METR 1014 class during the Fall 2005 semester.