Why is the ocean blue?
Show answer & explanation
Answer: Water absorbs red light
Water absorbs red light ✓ — Correct! Water molecules absorb different colors of light at different rates. Red, orange, and yellow light are absorbed more than blue light. In deep water, only blue light penetrates deeply and scatters back to our eyes. That's why shallow water looks clear but deep ocean appears blue. The same property makes ice and thick water appear blue too!
Salt turns water blue — Wrong. Salt doesn't make seawater blue - even pure fresh water appears blue when deep enough. The blue color comes from water absorbing red wavelengths while scattering blue light.
Blue algae color the water — Wrong. While algae can tint water green or brown, the ocean's blue color comes from water itself. Water absorbs red light and scatters blue light, making deep water appear blue.