I do want to seriously address one of the points on this page. Water is, in fact, blue. It sometimes appears green because of algae and other organisms in it.

I do want to seriously address one of the points on this page. Water is, in fact, blue. It sometimes appears green because of algae and other organisms in it. Here is a better explanation than I could have come up with: > The water is in fact not colorless; even pure water is not colorless, but has a slight blue tint to it, best seen when looking through a long column of water. The blueness in water is not caused by the scattering of light, which is responsible for the sky being blue. Rather, water blueness comes from the water molecules absorbing the red end of the spectrum of visible light. To be even more detailed, the absorption of light in water is due to the way the atoms vibrate and absorb different wavelengths of light. [0] Likewise, while nitrogen is colorless, oxygen is actually blue as well, which, in turn, means that air is actually slightly blue (this is not the cause of the blue sky -- see [1]). --- [0]: https://www.usgs.gov/special-topic/water-science-school/science/water-color?qt-science_center_objects=0#qt-science_center_objects https://www.usgs.gov/special-topic/water-science-school/scie... [1]: https://en.wikipedia.org/wiki/Rayleigh_scattering https://en.wikipedia.org/wiki/Rayleigh_scattering