I want you to color me blue1/1/2024 ![]() ![]() That's what's going on here, it would seem. It's hard to disprove a falsehood when it seems to fit so seamlessly with other true, if poorly understood, propositions. But what? Why?Ī little knowledge, it turns out, can be a dangerous thing. Such conviction and confidence when everything - when all the evidence - speaks loudly against, can only be the result of some prejudice or bias. Even people who have been cut, or have witnessed an accident scene, or had blood drawn, cleave to the conviction of blood's sometime blueness. You can imagine children - who may have never seen an accident, or been cut, or had blood drawn or taken a biology class - who might gullibly believe that blood is blue, because someone told them so. Here's a hypothesis: The problem is not outright ignorance. At a time when ignorant people openly challenge scientific knowledge about such important matters as the safety of vaccines or the dangers posed by the burning of fossil fuels, it seems worthwhile to try to understand why some bad ideas are so immune to revision. It's a politically neutral example of a bit of falsehood that seems resistant to information. Could it be that people have taken this to be a guide to their actual color? Or could the answer lie elsewhere? By convention arteries are drawn red in textbooks and veins blue. Maybe it is the fact that veins look bluish that explains the myth that blood is blue as it flows through the veins? (I think this also explains why your lips look blue when you get cold.) But if you were to open one of your veins, or cut your lip, even when you're cold, there'd be nothing blue at all about the liquid that would pour forth. But the short of it is this: It has to do with the way tissue absorbs, scatters and reflects light. Why should this be so? Click here if you want the full story. It is true that veins, which are sometimes visible through the skin, may look bluish. Blood does change color somewhat as oxygen is absorbed and replenished. It's red because of the red blood cells (hemoglobin). We also know why it is red, as already noted. If you get blood drawn, the liquid that comes from your vein into the vacuum sealed container is, plainly, red. ![]() Blood was shooting out of my arteries and sloshing out of my veins. When I was 12, I was in an accident and my left wrist was ripped open so that I could see into my arm. Here is some evidence that this isn't true. I bring this up because I've noticed that there are a fair number of people - some of the 7th graders my son goes to school with, some teachers, too, who ought to know better, as well as lots of people who have published online - who say that blood inside the body is sometimes blue. And it's still red, but darker now, when it rushes home to the heart through the veins. ![]() ![]() It's bright red when the arteries carry it in its oxygen-rich state throughout the body. The blood of a vulcan is green, according to the story anyway, and this is presumably because the stuff that carries oxygen in the vulcan's blood is green.īut our blood is red. This is because the protein transporting oxygen in their blood, hemocyanin, is actually blue. Octopuses and horseshoe crabs have blue blood. Human blood is red because hemoglobin, which is carried in the blood and functions to transport oxygen, is iron-rich and red in color. This isn't because it isn't really red, but rather because its redness is a macroscopic feature. ![]()
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