Question

Wet clothes dry more quickly on a hot, dry day than on a hot, humid day. Explain.

Short answer

Wet clothes dry faster on a hot, dry day because the air is not saturated with water vapor, meaning it can accept more water vapor from the clothes. The high temperature also increases the evaporation rate, thus accelerating the drying process.

Step-by-step solution

Understanding Evaporation

Firstly, it's crucial to understand that drying involves the process of evaporation, which is the transformation of liquid water into water vapor. In the case of wet clothes, the liquid water in the clothes will become water vapor and dissipate into the air.

Effect of Temperature on Evaporation

The higher the temperature, the faster the rate of evaporation. This is because molecules in a liquid have different energies and at higher temperatures, more molecules have the necessary energy to transform into a gas and leave the liquid.

Understanding Humidity

Humidity refers to the amount of water vapor in the air. On a humid day, the air is already saturated with water vapor, making it harder for additional vapor - such as that from our wet clothes - to be added to it.

Effect of Humidity on Evaporation

When the air is saturated with water vapor, it reduces the evaporation rate because the air is unable to accept more water vapor. Hence, on a hot, humid day, because the air is saturated or nearly so with water vapor, additional water vapor from the wet clothes cannot easily enter the air, hence they dry slowly.

Putting it all together

Therefore, wet clothes dry more quickly on a hot, dry day due because the air has a lower saturation of water vapor, allowing more water to evaporate from the clothes, and the high temperature increases the evaporation rate.