Does blood actually turn blue when not oxygenated? If it doesn’t, then why do some veins appear to be blue? These are the questions that need to be answered in today’s society.

It is a known fact that blood does not turn blue, but some may point out that some veins appear to be blue. While this does sound like the beginning of a crazy conspiracy involving the medical world, it is actually pretty easy to explain.

Blood is always some shade of red, but when looking at a vein, one must account for the color of the blood, the color of the vein’s walls, and the color of the skin. The walls of veins and skin are not clear, therefore veins will not appear the same color as the blood inside of them.

The UCSB ScienceLine makes a good point when it states that Sprite may look green from the outside, but the actual liquid is clear. The bottle affects how the drink looks from the outside.

In a nutshell, that is what is happening when you see a blue vein. It is not that the blood is blue, but all of the different colors from the blood, the vein wall, and the skin are making it appear blue.

So, now when anyone questions why veins are blue, you can impress them with some crazy science facts!

SOURCES:

http://scienceline.ucsb.edu/getkey.php?key=2927