Why are clouds bright white?
You know those fluffy white clouds that look like wooly sheep or whipped cream? Why are they so white?
When I type in "why are clouds white?" into a Google search, the top 10 links all agree that the whiteness is due to the scattering of light by water droplets within the cloud.
I would politely like to disagree. My goal in this article is to show you why this does not make sense. There is a better explanation, a simpler one. Of course, the caveat is that I am not a meteorologist. But, read on, and see what you agree with.
Clouds are white because disorganized air bubbles produce the white color
First: A lot of what we see as white is due to trapped air bubbles
Of note, not all white color in nature is due to entrapped air. Read more in this course.
Clouds are dark when water absorbs light
Second: Larger water droplets eat up the light --> darkness
Have you noticed that as soon as the rain stops that the clouds no longer have that darkened structure?
Snow and ice without air appear clear or blue
Third: Add air to snow and ice ------ whiteness
In summary, it does not matter how much water/ice the cloud has. As long as there is a mass of disorganized air bubbles at the forefront of the cloud, the cloud will appear white. Thus, the tops of clouds - seen from an airplane - appear very white. That is the edge of the cloud with an expanding air mass. The bottom of a storm cloud will appear dark or grey; that is where water/ice are getting larger and weighing down the cloud. The dense number of large water drops absorb light creating the darkness effect.
- Header image: Images by John 'K'. "Flat bottomed clouds", March 4, 2009.
- Vladimer Shioshvili. Clouds in Dusheti, Georgia, May 21, 2006.
- David Masters. Happy Sheep. One of the sheep at Styal Country Park, Cheshire, Feb 15, 2009.
- Martin Garrido. Beer, Dec 27, 2011.
- devra . Spittling crab in Morro State Park Marina, July 5, 2010.
- Better Than Bacon. Polar bear in California. Apparently their hairs aren't white, they're actually translucent but hollow to better insulate, Aug 4, 2007.
- Maxwell Hamilton. Unusual Clouds; Altostratus undulatus, March 30, 2015.
- Paulo O. Storm Clouds Over Fairfax, April 27, 2011.
- Nicholas A. Tonelli. Convergence, Nimbostratus streaks, Easton, March 24, 2007.
- anoldent. Blue ice cave, 2000 New Zealand 108.
- Hijab, J. Clear ice cubes, 2018.
- Hijab, J. White snow on deck, 2018.
- Hijab, J. Ice cubes with trapped air bubbles.