Relative humidity

Definition

Relative humidity is the ratio of the current amount of water vapor in the air to the maximum amount that the air can hold at a given temperature, expressed as a percentage. It indicates how close the air is to being saturated with moisture.

5 Must Know Facts For Your Next Test

1. Relative humidity depends on both the moisture content and temperature of the air.
2. When relative humidity reaches 100%, the air is fully saturated, leading to condensation and possibly precipitation.
3. Relative humidity affects evaporation rates; lower relative humidity increases evaporation.
4. It is measured using instruments like hygrometers and sling psychrometers.
5. Relative humidity plays a crucial role in human comfort and weather forecasting.

Review Questions

• What happens when relative humidity reaches 100%?
• How does relative humidity affect evaporation rates?
• What instruments are used to measure relative humidity?

Related terms

Absolute Humidity: The total mass of water vapor present in a given volume or mass of air, usually expressed in grams per cubic meter.

Dew Point: The temperature at which air becomes saturated with moisture and dew forms.

Saturation Vapor Pressure: The pressure exerted by water vapor in equilibrium with liquid water at a given temperature.