Mercury barometers used to measure air pressure. Credit: Edal Anton Lefterov/Creative Commons

Pressure is a measurement of force per unit area. Unfortunately, there are many different units associated with pressure and these units are still used in a variety of applications. Atmospheres (atm) is a common unit when working with gasses and the pascal is the SI unit of pressure equal to one newton per square meter (N/m^{2}). Pascal represents a very small pressure so the larger kilopascal (kPa) is used more often when working with larger pressures. This example problem shows how to convert atm to kPa units.

Example Problem: The pressure at sea level is generally considered to be 1 atm. Pressure increases the deeper you dive in the ocean by roughly 1 atm every 10 meters. At a depth of 50 meters the pressure will be 5 atm. What is this pressure in kPa?

Solution: The relationship between atm and Pa is:

1 atm = 1.013 x 10^{5} Pa

The other relationship needed is the number of pascals in a kilopascals.

1 kPa = 1000 Pa

Multiply 5 atm by these conversion factors to calculate kPa.

? kPa = 506.5 kPa

Answer: The pressure 50 meters underwater is equal to 506.5 kPa.