How do wet-bulb and dry-bulb temperatures differ and what do they represent?

How do wet-bulb and dry-bulb temperatures differ and what do they represent?

• A. Dry-bulb is ambient temperature; wet-bulb reflects evaporative cooling and humidity effects.
• B. Dry-bulb measures humidity; wet-bulb measures air pressure.
• C. Dry-bulb is dew point; wet-bulb is ambient temperature.
• D. Dry-bulb is indoor temperature; wet-bulb is outdoor temperature.

Answer: (A)

The main idea is that the dry-bulb temperature is the actual ambient air temperature, while the wet-bulb temperature reflects evaporative cooling and humidity effects. A dry-bulb reading comes from a standard thermometer exposed to the air, so it shows how hot or cold the air is. The wet-bulb reading comes from a thermometer with a moistened wick; as air flows over it, water evaporates and cools the sensor. How much it cools depends on how dry the air is and how fast air moves, so the difference between the two readings shows the role of evaporative cooling and humidity. In dry air the wet-bulb can be noticeably cooler than the dry-bulb; in humid air evaporation slows and the two readings are close. This is why the wet-bulb temperature represents evaporative cooling and humidity effects, while the dry-bulb temperature is simply the ambient air temperature. The other options mix up what each thermometer measures or introduce unrelated quantities like humidity, air pressure, dew point, or indoor/outdoor temperature.

The main idea is that the dry-bulb temperature is the actual ambient air temperature, while the wet-bulb temperature reflects evaporative cooling and humidity effects. A dry-bulb reading comes from a standard thermometer exposed to the air, so it shows how hot or cold the air is. The wet-bulb reading comes from a thermometer with a moistened wick; as air flows over it, water evaporates and cools the sensor. How much it cools depends on how dry the air is and how fast air moves, so the difference between the two readings shows the role of evaporative cooling and humidity. In dry air the wet-bulb can be noticeably cooler than the dry-bulb; in humid air evaporation slows and the two readings are close. This is why the wet-bulb temperature represents evaporative cooling and humidity effects, while the dry-bulb temperature is simply the ambient air temperature. The other options mix up what each thermometer measures or introduce unrelated quantities like humidity, air pressure, dew point, or indoor/outdoor temperature.