this post was submitted on 13 Oct 2025
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It's not like it doesn't have some logic to it. Blood carries oxygen throughout the body and then cycles back through the lungs to get more oxygen. So when you look at your arms and see the blue veins we just thought that was obviously the deoxygenated blood returning to the heart.
It made basic sense, so no one was running down to the library to check out a medical textbook to disprove it.
Ever see a blood draw? Blood comes out of a vein, into a non-O2 environment.
I think we just don't do as much critical introspection as we like to think. Its easier to imagine maybe there was a tiny amount of O2 or something than that the thing we were taught was entirely false.
It's definitely true, and it shows that the stuff you learn as kids is even more ingrained than we even notice most of the time. Kids don't normally have blood drawn, so it's not like elementary schools were filled with a bunch of kids saying "wait a minute, that didn't happen with my last blood draw."
There were actually about 5 of us that contested it and she tried to say "they drew that blood from your arteries"
You look when they draw blood?
Yes. Its neat. You dont?
My first thought was how ears and noses look red when sunlight shines through them. If blood was blue, wouldn't they be blue or purple?
Veins appear blue because the skin and veins refract the light to permeating the skin causing the wavelenths to appear blue. It was well known in the early 2000s. She was just stupid and had no business teaching science.