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.
More Physics in Daily Life questions
- In a warm office that already reads 26 C, which change can make people feel cooler without lowering the thermostat?
- Why might 26 C feel acceptable in a breezy naturally ventilated summer building but too warm in a sealed winter office?
- On a warm humid day, why can the same 27 C room feel much worse once you start sweating?
- Why can moving air make a 27 C room feel cooler without changing the thermometer?
- Which hidden factor can make a desk beside a cold window feel chilly even when the thermostat across the room still reads 22 C?
- In the same 22 C room, why might someone who just climbed stairs feel warm while someone sitting in a T-shirt feels chilly?