Boyle’s Law describes the relationship between pressure and volume of a gas. Matt Wandell, a biologist at the California Academy of Sciences, demonstrates Boyle’s Law by placing a balloon in a small decompression chamber to simulate what happens to a fish’s swim bladder at different pressures. A swim bladder is a gas-filled organ in fish that helps them maintain their buoyancy. An animation in the video reveals how the gases inside the balloon behave in response to pressure change. This Science Spotlight is a companion video to Bringing Fish Up from the Deep and is part of our Engineering Is: Bringing Fish Up from the Deep e-book. The e-book explores the science and engineering principles behind the California Academy of Sciences’ portable decompression chamber, and includes videos, interactives and media making opportunities. You can find our other e-books at kqed.org/ebooks.