NCIDQ IDFX Practice Exam

What process occurs when moisture changes to vapor as a person perspires or breathes?

1. Evaporation

2. Convection

3. Condensation

4. Radiation

The correct answer is: Evaporation

The process that occurs when moisture changes to vapor as a person perspires or breathes is evaporation. This phenomenon happens when the molecules in a liquid gain enough energy to transition into a gaseous state. When a person sweats, the moisture on the skin's surface absorbs heat from the body, causing it to evaporate. This process helps in regulating body temperature by cooling the skin as the sweat transitions to vapor and dissipates into the air. In contrast, convection involves the movement of air or fluid and the transfer of heat through that movement, while condensation is the opposite process, where vapor changes back into liquid. Radiation refers to the transfer of heat in the form of electromagnetic waves, such as infrared radiation. Understanding the concept of evaporation is crucial in the context of thermal comfort and human physiology, particularly in environments where bodily moisture management is essential for maintaining a comfortable temperature.