Constants Used For the Dive Theory Exam

[Pedro Burrito]

The following are the constants used for the PADI Dive Theory Exam:

Metric

• 1 litre of salt water weighs 1.03 kilograms
• 1 litre of fresh water weighs 1 kilogram
• Pressure increases by 1 ATM every 10 metres of salt water
• Pressure increases by 1 ATM every 10.3 metres of fresh water
• Pressure changes per unit of salt water = 0.100 ATM/m
• Pressure changes per unit of fresh water = 0.097 ATM/m

Imperial

• 1 cubic foot of salt water weighs 64 pounds
• 1 cubic foot of fresh water weighs 62.4 pounds
• Pressure increases by 1 ATM every 33 feet of salt water
• Pressure increases by 1 ATM every 34 feet of fresh water
• Pressure changes per unit of salt water = 0.445 psi/ft or 0.0303 ATM/ft
• Pressure changes per unit of fresh water = 0.432 psi/ft or 0.0294 ATM/ft