Absolute humidity

Absolute humidity is the amount of water vapor in the air. It is measured by the amount of water vapor, in grams, present in a certain volume of air. Water vapor is invisible and doesn't normally stick together so it is hard to measure. To measure absolute humidity, we use a device called a hygrometer. A hygrometer measures the amount of water vapor in the air so we can tell the absolute humidity. The higher the absolute humidity, the more water vapor is in the air.