An Atmosphere (atm) is a standardised unit of pressure. 1 atm = 101,325 PA It is not an SI unit but it is widely used and very useful in situations, such as t

An Atmosphere (atm) is a standardised unit of pressure. 1 atm = 101,325 PA It is not an SI unit but it is widely used and very useful in situations, such as this, where pressure relative to atmospheric pressure is relevant.