Pressure is a concept that can be confusing for some. There are the pressures and stress associated with daily tasks like school work, homework, jobs and chores. There are also the pressures associated with science. We’re going to look at the science aspect of pressure.
Pressure is mostly simply described as an amount of force applied to a given amount of area. Pressure can be used to describe many different applications.
In the U.S. we typically use PSI units to describe pressure. PSI is an acronym for Pounds per Square Inch. The unit itself is fairly explanatory as to how much force per unit of area is applied. Imagine a five pound force being applied to a one square inch area. That would be equal to 5 PSI. If you have 10 pounds applied to a 1 square inch area, that would be 10 PSI. If you increase the amount of area that the force is applied to but keep the amount of force the same, the pressure decreases. If you have 10 pounds of force that is applied to 2 square inches, you now have a pressure of 5 PSI.
Many times, pressure refers to an application that involves gaseous liquids. Although PSI can be used to describe pressure in these applications, you most likely will see a unit of pressure called a Pascal, or a derivative of Pascal like KiloPascals. Sometimes the unit of Bar may be used to describe gaseous pressures.
In regards to atmospheric pressure, there are also many ways to describe air pressure. Atmospheric pressure depends on many factors like temperature, humidity and altitude. Sometimes atmospheric pressure will be measured in PSI or Inches of Mercury. Inches of Mercury is a traditional way to measure how dense the air in the atmosphere really is.
This was just a quick mention of some of the ways that pressure is measured. For more information on how to convert between units, try some of the calculators at CalcuNATION.