In a diving-related scenario, which law explains the development of joint pain after a rapid ascent due to gas coming out of solution?

• A. Boyle's Law
• B. Henry's Law
• C. Dalton's Law
• D. Charles' Law

Answer: (B)

Gas dissolving in liquids is governed by Henry's Law: the amount of dissolved gas in a liquid is proportional to the partial pressure of that gas above the liquid. At depth, higher ambient pressure forces more nitrogen into tissues. If ascent is rapid, the ambient pressure drops quickly, reducing the gas’s solubility and causing dissolved nitrogen to come out of solution as bubbles. These bubbles can form in joints, leading to the joint pain often seen with decompression sickness. The other laws describe different aspects of gas behavior (volume changes with pressure, partial pressures in mixtures, and temperature effects on gas volume) and don’t explain dissolution into tissues.