| MadSci Network: Physics |
As light penetrate deeper in water, it loses more of its components at longer wavelengths (i.e., green, yellow, red) because of stronger absorption by water molecules. Therefore in ocean, the ambient appears bluer and darker as you do deeper: darker is because overall more light are absorbed by water. It will reach total darkness after certain depth. In the swimming pool, the differences are 1) water is shallow and 2) there is highly reflective bottom (as compared to sand or soil bottom in the ocean). Because of this, swimming pool often appears brighter green as compared to the deep blue color of ocean. The shades of red that you've observed is probably because a particular angle you were looking at. I would guess it is like rainbow (refractive index varies at different wavelength). In your case, it caused the reflected light from the bottom to disperse.
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