Humidity Notes:
Vocabulary words: water vapor, humidity, evaporation,
condensation, relative humidity
Tool used to measure humidity is called a Hygrometer.
It measures the amount of water vapor in the air.
There are two factors that determine the amount of
humidity in the air:
1) There has to be enough water available to
evaporate.
2) The warmer the temperature, the faster the
water evaporates.
There are three ways warm, moist air cools off:
1) Air can cool by being pushed upward over
mountains by wind.
2) Heating air also causes it to rise. When the sun
heats the ground, air above the ground warms
and rises. As it rises, it expands and cools.
3) Air can be pushed upward when cooler air and
warmer air meet. When the two meet, they
don’t mix. The lighter, warm air is pushed up
over the heavier cold air. As a result, the warm
air, pushed higher into the atmosphere, cools.
These actions all have one result: As the air rises and
cools, the water vapor in it cools and condenses into
tiny water droplets, forming clouds.