A deep-sea scientific submersible is equipped with an emergency breathing apparatus for its crew.
The oxygen cylinder has a volume of 16 litres16\text{ litres}16 litres and contains oxygen compressed to 165165165 times normal atmospheric pressure. The oxygen is released to the cabin at normal atmospheric pressure. The crew consumes oxygen at a combined rate of 15 litres15\text{ litres}15 litres per minute (measured at normal atmospheric pressure).
Calculate the maximum duration (in minutes) that the crew can be sustained using this cylinder.
During a ballast-release maneuver, gas bubbles are discharged from the submersible and rise toward the ocean surface. Explain why these bubbles expand as they rise.