The sky is always changing colors—from a bright blue on a clear day, to red and orange sunrises or sunsets, or multiple colors of a rainbow—there’s a lot going on that we don’t always think about.

Cotton candy-colored sunsets are my favorite, and I'm sure you have your favorites too. Have you ever wondered why we see certain colors sometimes ... wildfire smoke, water vapor, and overall ...

One thing you may have noticed, if you were lucky enough to spot one, was that the color pattern was inverted. The seven colors of a rainbow go ... twice inside the water droplet.

But birds have four color cones, meaning they are tetrachromatic. With our three color cones, we can see the colors of the rainbow—red ... a small amount of sugary water or plain water.

sandid/pixabay This rainbow glows a vibrant red, lacking the rest of OY G. BIV. Jason Campbell via Wikimedia Commons, CC-BY-3.0 Yellow and red are the primary colors in this double rainbow.