Humidity, evaporation, and condensation

In cooled saturated air extra water vapour can change into droplets. For exams remember condensation after saturation.

In high humidity air takes less new moisture so evaporation slows down. For exams connect high humidity with slow evaporation.

Mist and fog are linked with tiny water droplets near the ground. For exams remember them as condensation near the surface.

Most weather events occur in the troposphere and water vapour is important there. For exams remember weather and troposphere together.

Evaporation adds water to the atmosphere as water vapour. For exams treat evaporation as a process that increases atmospheric moisture.

Clouds form through condensation of water vapour. For exams consider condensation essential for cloud formation.

Atmospheric moisture mainly remains in the form of water vapour. For exams connect humidity with the presence of water vapour.

Heat and dryness together change water into vapour quickly. For exams connect hot dry weather with high evaporation.

Evaporation and transpiration both add water vapour to the atmosphere. For exams remember both as sources of moisture.

When air has less water vapour it can take more moisture so evaporation can become faster. For exams connect low humidity with faster evaporation.

On a cold night the ground cools and nearby water vapour condenses to form dew. For exams remember a cold surface for dew formation.

At dew point air becomes saturated and water vapour can change into droplets. For exams connect dew point with the start of condensation.

The amount of water vapour in air is called humidity. For exams, connect humidity directly with water vapour.

Air holding maximum water vapour at a given temperature is saturated air. After saturation, cooling can easily cause condensation.

Specific humidity shows the share of water vapour in the mass of air. It does not change as quickly with temperature as relative humidity.

Warm air can hold more water vapour, so relative humidity falls when moisture remains the same. Remember the link between temperature and capacity.

Cool air can hold less water vapour, so the same moisture becomes a higher percentage. This prepares conditions for condensation.

Dew point is the temperature at which air becomes saturated and water vapour starts condensing. Remember dew point with condensation.

In evaporation, liquid water changes from its surface into water vapour, which is the gaseous state. Therefore, vapour state is correct. Change into ice or a solid occurs by freezing, not by evaporation. Exam tip: evaporation takes place only at the surface of a liquid.

Strong wind removes moist air above the surface and increases evaporation. Wind speed is an important factor in evaporation.