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How to Prove Blood Is Red

  1. Mar 18, 2010 #1
    My brother is under the misconception that blood is blue.

    I'm not that good with explaining things, but so far I have convinced my dad that blood is red. My brother just does not believe that blood is red and not blue.

    What are some facts to disprove the misconception that blood is blue?

    I am in 9th Grade taking AP Bio and my brother is in 10th grade taking Bio, so please keep it as simple as you can. Or I can just simplify it for him 'cause he won't understand anything I will say. Also the fact that he thinks just because he's older, it means he's smarter.

    So what are some explanations?
  2. jcsd
  3. Mar 18, 2010 #2
    Show him so blood and ask him why it's red. When he says whatever reason he thinks it turns red then ask him HOW that occured. It'll show he doesn't actually understand. Hemoglobin can not be blue, it's just not possible you would have to take the Fe2+ ion out and put something in it's place to make it blue.

    Anyways a simple way to 'prove' that blood is red is to take your brother to a blood donor clinic. Get him to donate some blood and you'll notice, the blood is a dark red possible looking sorta brownish. This blood is veinous, aka not oxygenated, blood. The blood doesn't contact oxygen during it's trip into the bag. If you do this you'll accomplish two things, you'll be correcting your elder brothers misconception on the colour of blood and you will be getting him to do a good thing in the process by donating blood :smile:
  4. Mar 18, 2010 #3
    Ah yes. I told him that hemoglobin cannot be red before, but could not explain how I know. I knew it was not possible, but was not sure why not either. Thanks for helping me [and my brother] out.
  5. Mar 18, 2010 #4

    Andy Resnick

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  6. Mar 18, 2010 #5


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    Good thing we can safely assume his brother is not a horseshoe crab, or a plant...:rofl:
  7. Mar 18, 2010 #6


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    Honestly, if he thinks blood is blue against life experience (I don't believe he never cut himself) assumption that he is neither plant nor crab doesn't seem so obvious.
  8. Mar 18, 2010 #7


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    I'm pretty confused here. Has he never cut himself before?

    or does he want a WHY?
  9. Mar 18, 2010 #8


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    I'm sure the brother is talking about deoxygenated blood. It's a popular misconception, actually -- helped by the appearance of veins through the skin, I think. (Also perhaps helped by the expression "blue-blooded"?)
  10. Mar 18, 2010 #9


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    He’s just misled by the veins color beneath his skin, as CRGreathouse have said... The only safe proof is to pin him with a needle! I assure you he'll never forget that :biggrin:
    Last edited: Mar 18, 2010
  11. Mar 18, 2010 #10
    For your brother,you may take him where someone are killing the pig or duck and so on.Then he can see the blood is red himself
  12. Mar 18, 2010 #11


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    First, an obvious question, does your brother have an undiagnosed color blindness ?

  13. Mar 18, 2010 #12
  14. Mar 18, 2010 #13


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    I have a feeling his conception is that deoxygenated blood is blue, but that the moment you prick yourself, it becomes immediately oxygenated and turns red.

    The only way he will be convinced the blood is not blue is to show him veinous blood that has not been exposed to oxygen.

    Also, I have the feeling that, given the fact that he is your older brother, he is simply yanking your chain in a lifelong effort to drive you crazy.
  15. Mar 18, 2010 #14
    Thats what i thought too!
    Thanks for the confirmation
  16. Mar 18, 2010 #15
    Neither of those are hemoglobin and they are quite different if you study them. Just because it's part of another organisms blood does not mean it's hemoglobin.

    Anyways I had mentioned in my post that you could change the colour of blood with:

    Besides the Cu+2 ion may not even be blue in humans as it's colour changes quite a bit in various pH levels. It may turn out more greenish...
  17. Mar 19, 2010 #16
    That's a popular myth that people still believe.
    The myth is: "Blood is blue in your body until it touches the oxygen in the air and turns red. That's why you can't ever see it blue, because it turns red immediately when it hits the oxygen."

    The stupid idiots ignore the fact that your blood has oxygen in it already while it's still in your body.
  18. Mar 19, 2010 #17


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    So teh simplest way is to draw some blood into the syringe - it avoids contact with the air this way.
  19. Mar 19, 2010 #18
    Not true, because hardly any grade 10 would know if they were seeing veinous or oxygenated blood. As well it could be dangerous... I think my suggestion of going to a blood bank would be the best, that way it's safe and you it's a sure thing that what you see being extracted is veinous blood that has not been oxygenated. It's also a sure thing that it never contacted any air during the trip.
  20. Mar 19, 2010 #19


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    Both are red. They differ in shade, but neither is blue.

    And I was not proposing to draw you own blood, that was rather general idea how to approach the problem.
  21. Mar 19, 2010 #20
    Yes, I know they are both red, however the problem is that the misconception is that veinous blood is blue (deoxygenated) and turns red upon receiving oxygen. Your suggestion is good but I think the OP was looking for a more realistic solution which he could use to show that the misconception is false. If they had drawn blood using a syringe they wouldn't be able to tell the difference (more than likely) and may even have a mixed sample of veinous and arterial blood which compromises the results.
  22. Mar 19, 2010 #21
    My bro thinks that deoxygenated blood is blue, just to clear things up.
    I told him about the hemoglobin, but I think it just went over his head. And when I told him about the 'drawing blood from veins' thing and he decided to ask me how it's possible for the syringe to be clear of oxygen. He's not a science guy, so when I talk about something that involves some degree of science, it goes right over his head.

    He was brought under the misconception by his biology teacher and his biology teacher learned it from her professor in college(I think my brother/his teacher made up the professor thing, but maybe my brother misunderstood what his teacher was saying. He tends to not pay full attention sometimes)
  23. Mar 19, 2010 #22
    Well if he doesn't believe that when blood is drawn there isn't oxygen in the bag or tube etc. then... just a lost cause. There's absolutely no way to prove to him that human blood is red. He doesn't understand the chemistry and he doesn't 'believe' the proof. So basically he just believes it 'just because' without having any evidence to support the position.

    It's entirely plausible though that he's just yanking your chain though... that tends to happen a lot in brotherly love relationships :wink:.
  24. Mar 19, 2010 #23
    Nah, I can tell he's not messing with me. But as you said, he does not understand the chemistry nor does he believe the proofs. I already proved to him why it's red through 3 explanations, but he's not accepting it, I guess.
  25. Mar 19, 2010 #24
    Some people get stuck with one idea because they want it to be true.
    For example, someone can find some false information online and automatically believe it, yet no amount of further online information debunking that false claim will ever convince them.
  26. Mar 19, 2010 #25


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    Does he realize that the very functioning of a syringe requires that it not have anything in it at all? That's how it draws blood out. Pulling back on the plunger draws blood into the vacuum.
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