Measuring Humidity
Humidity is measured as a percentage, or a part, of all of the air in a certain area.
In this picture, you can see the words 'Humidity 53%,' which is read as ''Humidity fifty-three percent.'' This means that out of all of the air being measured (100% of it), 53 out of 100 parts are made up of water vapor. The air in this report would be completely filled with water vapor if the humidity were 100%.
This way of reporting humidity is called relative humidity. It depends on the air that is being sampled. Warm air can hold more humidity than cold air can, so 53% humidity on a cold winter day would mean more water vapor than 53% humidity on a hot summer day.
Humidity in Our World
The air we take into our bodies has different amounts of humidity in it every day. Air temperature, plant transpiration, human breathing, and natural water sources all cause these day-to-day changes.
We can feel the different levels of humidity in the air around us. Going back to the example of a hot shower, think about the way your skin almost feels wet even before you enter the shower. Or if you go on a trip to somewhere very humid, like South Florida, when you get off the plane, you can feel the air feels thicker and warm - that's humidity!
High levels of humidity also cause changes in the climate, or usual weather patterns, on Earth. Water vapor is one of the gases that causes the Earth's atmosphere to get hotter than it should be. This is something known as the Greenhouse Effect.
Lesson Summary
Humidity is the name for the amount of water vapor in the air. Water vapor is water in its gas form. In weather reports, this is reported as the percentage,, or part of a whole, of the air that's filled with water vapor. Relative humidity is a way of reporting humidity that depends on the air that's being sampled.
Water vapor is produced when humans and animals breathe, when water evaporates from oceans and other water sources, and when plants release extra water into the atmosphere. Humidity makes our skin feel wet, even when we are not directly touching liquid water, and affects the Earth's atmosphere, making it warmer that it would be with less humidity.
