Photo: Asif pav

What Colour is blood?

red It's red because of the red blood cells (hemoglobin). Blood does change color somewhat as oxygen is absorbed and replenished. But it doesn't change from red to blue. It changes from red to dark red.

npr.org - Why Do Many Think Human Blood Is Sometimes Blue? - NPR

What to invest $1,000 in right now?

Best ways to invest $1,000 right now Pay off high-interest debt. Start an emergency fund. Invest in Y-O-U! Buy pieces of your favorite companies...

Last updated May 25, 2018

What are the 2 laws of God?

“Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. “This is the first and great commandment. “And...

Last updated Feb 5, 2019

Awaken your dormant DNA ability to attract wealth effortlessly

The simple yet scientifically proven Wealth DNA method laid out in the report allows you to effortlessly start attracting the wealth and abundance you deserve.

Learn More »

Promotion

Why Do Many Think Human Blood Is Sometimes Blue?

Blood is red to the naked eye. Under a microscope, it depends.

This isn't because it isn't really red, but rather because its redness is a macroscopic feature. Human blood is red because hemoglobin, which is carried in the blood and functions to transport oxygen, is iron-rich and red in color. Octopuses and horseshoe crabs have blue blood. This is because the protein transporting oxygen in their blood, hemocyanin, is actually blue. 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. But our blood is red. It's bright red when the arteries carry it in its oxygen-rich state throughout the body. And it's still red, but darker now, when it rushes home to the heart through the veins. 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.

Blue?

Here is some evidence that this isn't true.

When I was 12, I was in an accident and my left wrist was ripped open so that I could see into my arm. Everything was red. Blood was shooting out of my arteries and sloshing out of my veins. And all of it was red. Here's another piece of evidence. If you get blood drawn, the liquid that comes from your vein into the vacuum sealed container is, plainly, red. We also know why it is red, as already noted. It's red because of the red blood cells (hemoglobin). Blood does change color somewhat as oxygen is absorbed and replenished. But it doesn't change from red to blue. It changes from red to dark red. It is true that veins, which are sometimes visible through the skin, may look bluish. Why should this be so? Click here if you want the full story. But the short of it is this: It has to do with the way tissue absorbs, scatters and reflects light. (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.

Maybe it is the fact that veins look bluish that explains the myth that blood is blue as it flows through the veins?

Why do billionaires live so long?

Conclusions. It's not surprising that those with more wealth tend to live longer than those with less. If you have more money, you probably have...

Last updated Oct 6, 2020

Which zodiac signs are loyal?

Here are the zodiac signs that are the most loyal partners, in order of most to least likely to stay faithful. Scorpio (October 23 - November 21)...

Last updated Nov 17, 2022

Awaken your dormant DNA ability to attract wealth effortlessly

The simple yet scientifically proven Wealth DNA method laid out in the report allows you to effortlessly start attracting the wealth and abundance you deserve.

Learn More »

Promotion

Or could the answer lie elsewhere? By convention arteries are drawn red in textbooks and veins blue. Could it be that people have taken this to be a guide to their actual color?

I think this is worth understanding. It's a politically neutral example of a bit of falsehood that seems resistant to information. 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.

Here's a hypothesis: The problem is not outright ignorance. 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. 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. Such conviction and confidence when everything — when all the evidence — speaks loudly against, can only be the result of some prejudice or bias. But what? Why?

A little knowledge, it turns out, can be a dangerous thing. It's hard to disprove a falsehood when it seems to fit so seamlessly with other true, if poorly understood, propositions. That's what's going on here, it would seem. Take a little blood chemistry, exposure to textbooks and the sight of your own naked arms, and you get a perfect ecosystem in which to nourish a manifestly false belief.

Thanks to Ulysses Noë for adding to this discussion.

Alva Noë is a philosopher at the University of California, Berkeley where he writes and teaches about perception, consciousness and art. He is the author of several books, including his latest, Strange Tools: Art and Human Nature (Farrar, Straus and Giroux, 2015). You can keep up with more of what Alva is thinking on Facebook and on Twitter: @alvanoe

npr.org - Why Do Many Think Human Blood Is Sometimes Blue? - NPR

What is the lucky fruit of 2022?

Lychees are an auspicious fruit according to feng shui principles. Its red colour symbolises romance and good fortune. According to ancient Chinese...

Last updated Mar 9, 2022

What are anxiety affirmations?

Simply, positive affirmations for anxiety are mantras or phrases a person repeats to himself to describe who they want to become or a specific...

Last updated Sep 29, 2020

Awaken your dormant DNA ability to attract wealth effortlessly

The simple yet scientifically proven Wealth DNA method laid out in the report allows you to effortlessly start attracting the wealth and abundance you deserve.

Learn More »

Promotion

Who should a Virgo marry?

When looking for a person to marry a Virgo should look for signs such as Taurus, Cancer, and Scorpio and should usually stay away from another...

Last updated Dec 10, 2018

Awaken your dormant DNA ability to attract wealth effortlessly

The simple yet scientifically proven Wealth DNA method laid out in the report allows you to effortlessly start attracting the wealth and abundance you deserve.

Learn More »

Promotion

Is $60000 enough to retire on?

Plan to maintain your standard of living To accomplish this, financial experts say you'll need between 70-80% of your pre-retirement income. So,...

Last updated Feb 11, 2021