Two methods of measuring air pressure are BAR or:

Two methods of measuring air pressure are BAR or:

• A. Kilopascals
• B. Inches of mercury
• C. Pounds per square inch
• D. Atmospheres

Answer: (C)

Pressure is measured as a force per area, and in diving you’ll encounter two common ways to express it: bar and pounds per square inch. Bar is a metric unit, while psi (pounds per square inch) is the imperial counterpart. They describe the same physical quantity, with 1 bar about 14.5 psi. Gauges and regulators used in different regions reflect this, so psi is the natural second unit to pair with bar. Inches of mercury and atmospheres are other ways to express pressure in different contexts (barometric vs. atmospheric), and kilopascals are another metric unit, but in this pairing the practical alternative to bar is psi.

Pressure is measured as a force per area, and in diving you’ll encounter two common ways to express it: bar and pounds per square inch. Bar is a metric unit, while psi (pounds per square inch) is the imperial counterpart. They describe the same physical quantity, with 1 bar about 14.5 psi. Gauges and regulators used in different regions reflect this, so psi is the natural second unit to pair with bar. Inches of mercury and atmospheres are other ways to express pressure in different contexts (barometric vs. atmospheric), and kilopascals are another metric unit, but in this pairing the practical alternative to bar is psi.