Why Do We Use PSI and Pascals to Measure Pressure?

[supernova1203]

This isn't anything course related but i was just curious, why do we use several units for pressure? Primarily PSI and Pascals? Theyre both units used to measure pressure, but why are 2 units used? What are they similarities and differences? and where are they used?(situations scenarios) and what do they both mean? (i suppose psi = pounds per square inch so pressure per inch on a surface or object?)

 

[PhanthomJay]

This isn't anything course related but i was just curious, why do we use several units for pressure? Primarily PSI and Pascals? Theyre both units used to measure pressure, but why are 2 units used? What are they similarities and differences? and where are they used?(situations scenarios) and what do they both mean? (i suppose psi = pounds per square inch so pressure per inch on a surface or object?)

The United States and Myanmar use psi for pressure units, while all other countries (with a few holdouts)use Pascals (Newtons/square meter). The US system is the old Imperial System (Customary Units) which uses pounds as the force unit and feet or inches as the length unit (like 1 foot = 12 inches), whereas other countries use the more modern SI or Metric System units which uses Newtons as the force unit and meters as the length unit. (like 1 meter = 100 cm = 1000 mm). The SI system is easier to use because it is decimal based, whereas the US system is a random set of units. You can convert from one system to another by using conversion factors (like 1 meter = 3.28 feet). The Federal government of the US tried to mandate the SI conversion about 40 years ago, but failed to do so to this day, partly for ecomomic reasons associated with the change, and partly due to fierce opposition from engineers and contractors unfamiliar with SI. It is unlikely that full conversion to metric in the USA will take place in the foreseeable future, although manuals list values in both systems of measure just in case. Pressure values are units of force per unit area, like tire pressure, pump pressure, water pressure, or stresses in materials.

 

[ashishsinghal]

Just a tip: The title should give a hint of content in the thread.

 

[supernova1203]

Just a tip: The title should give a hint of content in the thread.

Yes i agree, also one can click the little "+" to see what's in the thread before even opening it to see what's in it.

 

[rwisz]

Great question! I am always curious about the units we use to measure different quantities. In the case of pressure, we do indeed use multiple units, including PSI (pounds per square inch) and Pascals.

The reason for this is that different industries and countries have historically used different units to measure pressure. For example, PSI is commonly used in the United States and is derived from the Imperial unit system, while Pascals are used in the International System of Units (SI) and are a metric unit.

Both PSI and Pascals are measures of pressure, but they differ in the amount of force and area they are measuring. PSI measures the amount of force in pounds applied to a surface, while Pascals measure the force in Newtons applied to a surface. However, both units ultimately measure the same thing - the amount of force per unit area.

In terms of situations and scenarios where these units are used, PSI is commonly used in industries such as automotive, aviation, and construction, where pressure is often measured in terms of pressure on tires, hydraulics, and other mechanical systems. Pascals, on the other hand, are used in scientific and research fields, such as meteorology, where pressure is measured in terms of atmospheric pressure.

In summary, while it may seem confusing to have multiple units for pressure, it is simply a result of historical and cultural differences. However, both PSI and Pascals are valid units of measurement for pressure, and their similarities and differences lie in the amount of force and area they are measuring.