PADI Open Water Diver Practice Test – Exam Prep & Study Guide

When a balloon filled with air is taken to the bottom of a swimming pool, it will get smaller due to the increase in water pressure at greater depths. According to Boyle's Law, the volume of a gas is inversely proportional to the pressure applied to it when temperature remains constant. As the balloon descends, the surrounding water pressure increases, causing the volume of the air inside the balloon to decrease.

Additionally, as the volume of the balloon shrinks, the air inside becomes more dense because the same amount of air is now occupying a smaller space. This phenomenon illustrates the principles of gas laws in action, demonstrating how pressure affects the volume of enclosed gases.

Consequently, while it is true that the increase in pressure will compress the air and make it denser, the other choices do not align with these fundamental principles of physics regarding gas behavior under pressure.