Wet-Bulb Temperature: Exploring the Science Behind Evaporative Cooling

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In summary, when a wet thermometer is placed in a 1 atm environment with a wet wick covering its bulb, the temperature of the water will drop during the process of evaporation. This is because evaporation removes high-kinetic-energy molecules, lowering the temperature of the water and creating a driving force for heat transfer. It has been observed that the temperature difference between a wet and dry thermometer can be as high as 10°C or more, indicating that water and air can have a significant difference in temperature in a real environment. This also means that they are not in thermal equilibrium until all the water has evaporated. While the mathematical explanation is not necessary for understanding, on a molecular level, the practical implications of this phenomenon are not
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Homework Statement


Imagine a wet thermometer whose bulb is covered with a wet wick at 1 atm. Temperature of the water happens to drop during the process of evaporation.

Homework Equations


N/A

The Attempt at a Solution


Does evaporation lower the temperature of water just by removing high-kinetic-energy molecules and lowers it's temperature, just so there can be a driving force for heat transfer? So basically heat from the air is supplied to the water resulting in lowering it's temperature by some small amount?

Somewhere I read that temeprature difference between wet and dry thermometer goes up to 10°C, or more. It's sort of shocking to me, does that mean that water and air at differ by that large amount in a real environment? So they are basically never in a thermal equilibrium until all water evaporates? Wow...

I'm not really interested in math behind it, i just don't get what's going on in molecular, practical level.
 
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What is wet-bulb temperature?

Wet-bulb temperature is a measure of the lowest temperature that can be reached through evaporative cooling. It is determined by measuring the temperature of a thermometer with a wet cloth over the bulb, which simulates the effect of evaporating water on the skin.

How is wet-bulb temperature different from dry-bulb temperature?

Dry-bulb temperature is a measure of the air temperature without taking into account the effect of moisture. Wet-bulb temperature, on the other hand, takes into account the cooling effect of evaporation and is a more accurate measure of how the air feels to us.

How does wet-bulb temperature impact the human body?

Wet-bulb temperature is an important factor in determining the level of heat stress on the human body. As wet-bulb temperature increases, it becomes more difficult for our bodies to cool down through perspiration, which can lead to heat exhaustion and even heat stroke.

What is the wet-bulb globe temperature index?

The wet-bulb globe temperature index (WBGT) is a measure of the combined effects of temperature, humidity, wind speed, and solar radiation on the human body. It is commonly used to determine safe levels of physical activity in hot and humid conditions.

How is wet-bulb temperature used in weather forecasting?

Wet-bulb temperature is an important factor in predicting the likelihood of thunderstorms and severe weather. When the wet-bulb temperature is close to the dry-bulb temperature, it indicates high levels of moisture in the air and an increased risk of precipitation and severe weather events.

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