How the air in a lift bag grows as the bag rises, by Boyle's law.
The formula: Boyle: V2 = V1 x P1/P2. Change any box and the full working updates. For study only, never for dive planning.
The IMCA ADS, BDS and LST papers ask this as a four-option question, with a calculator on screen. A free account gives you 15 practice questions for each exam, each with the worked answer and the document it comes from.