How does humidity impact the rate of evaporation?

Humidity significantly slows down the rate of evaporation because the air is already saturated with water vapour.

Evaporation is a process where water changes from its liquid state to a gaseous state, also known as water vapour. This process requires energy, usually in the form of heat, to break the bonds holding the water molecules together in the liquid state. The rate of evaporation is influenced by several factors, including temperature, wind speed, surface area, and humidity.

Humidity refers to the amount of water vapour present in the air. When the air is humid, it means that it is already holding a significant amount of water vapour. The higher the humidity, the less capacity the air has to hold additional water vapour. This is because air can only hold a certain amount of water vapour at a given temperature. When the air is fully saturated, or at 100% relative humidity, it cannot hold any more water vapour. This means that the rate of evaporation decreases as the humidity increases.

Imagine you're trying to dry your clothes outside. On a hot, dry day, your clothes will dry quickly because the air has a large capacity for water vapour. The water in your clothes evaporates into the air, turning from a liquid to a gas. However, on a hot, humid day, your clothes will take longer to dry. This is because the air is already saturated with water vapour and has less capacity to hold the water from your clothes. Therefore, the rate of evaporation is slower.

In summary, humidity plays a significant role in the rate of evaporation. The more humid the air, the slower the rate of evaporation, because the air's capacity to hold additional water vapour is reduced. This is an important concept to understand in various aspects of physics and meteorology.