Blaise Pascal, Isaac Newton, and Albert Einstein played a game of hide-and-seek. Einstein closed his eyes and counted to ten, while Newton ducked behind a wall. Pascal grabbed a piece of chalk and sketched a square with 1-meter sides.
When Einstein opened his eyes, he explained “Pascal, I’ve found you!”
But Pascal replied, “No, you’ve found one Pascal per square meter. You’ve found Newton!”
Ever since I heard that joke, I’ve never forgotten what a Pa was!
The Pascal (Pa) is a unit of measurement for pressure, which is equal to a newton per square meter (N/m2).
There are many units of pressure besides Pa, such as mbar, torr, and atm. However, Pa is the basic SI unit for pressure.
In materials science, we also use Pa to measure stress. Stress is the force per unit area, just like pressure. Pressure is usually the force that a gas exerts on an area, while stress is the force on the cross-section of a solid.
Pa is the SI unit of pressure, stress, strength, elastic modulus, and even hardness.
However, since these values are so high, usually thousands or millions of Pa, they are expressed in MPa or GPa.
MPa = 1,000 Pa
GPa = 1,000,000 Pa or 1,000 MPa
The pascal was named after Blaise Pascal, a French mathematician, theologian, and physicist. You may also have heard of Pascal’s wager or Pascal’s triangle.
This article was a definition of Pa. If you are interested in all the different, strange units that are used to measure pressure, I wrote an entire article explaining what each unit is, and how to convert between them. Or, if there is a unit you are especially interested in, you can check out one of the other unit definitions I’ve written.
Other Pressure Measurements:
mbar or bar
psi or ksi