**Pressure** is defined as the force per unit area exerted on a surface.^{[1]}

Imperial units used for air pressure include:

- atmospheres
- pounds per square inch (PSI)
- inches of mercury, which is the number of inches the given pressure will raise a column of mercury

The SI unit for pressure is the pascal (Pa), where 1 Pa = 1 N • m^{−2}. One atmosphere of pressure is equal to 101,325 Pa or 14.696 psi.

## See also

- blood pressure - typically measured in millimeters of mercury

## References

- ↑ Wile, Dr. Jay L.
*Exploring Creation With Chemistry*. Apologia Educational Ministries, Inc. 1998