Is the ocean blue at all depths? Nope! Explore the science behind the light spectrum in deep, dark waters. The activity recommends watching The Blue Planet: Open Ocean—The Deep, but it's not integral, or you can substitute another clip. Use the attached PowerPoint explain light penetration, bioluminescence, the photic zone, and light wavelength. Then, explore these new concepts using blue cellophane and a darkened classroom. As an assessment, scientists create a hypothetical deep-water animal and explain its adaptations.