Converting Atmospheres to Pascals

This example problem demonstrates how to convert the pressure units atmospheres (atm) to pascals (Pa). Pascal is a SI pressure unit that refers to newtons per square meter. Atmosphere originally was a unit related to the air pressure at sea level. It was later defined as 1.01325 x 10⁵ Pa.

Problem:

The pressure under the ocean increases roughly 0.1 atm per meter. At 1 km, the water pressure is 99.136 atmospheres. What is this pressure in pascals?

Solution:

1 atm = 1.01325 x 10⁵ Pa

Set up the conversion so the desired unit will be cancelled out. In this case, we want Pa to be the remaining unit.

pressure in Pa = (pressure in atm) x (1.01325 x 10⁵ Pa/1 atm)
pressure in Pa = (99.136 x 1.01325 x 10⁵) Pa
pressure in Pa = 1.0045 x 10⁷ Pa

Answer:

The water pressure at a depth of 1 km is 1.0045 x 10⁷ Pa.