Is Blood Red or Blue? Debunking Common Misconceptions

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Discussion Overview

The discussion revolves around the common misconception that blood is blue, particularly in the context of explaining this to a younger sibling. Participants explore various explanations and methods to demonstrate that blood is red, addressing both biological and experiential aspects.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants suggest demonstrating the color of blood by taking the sibling to a blood donor clinic to observe dark red venous blood.
  • Others argue that hemoglobin cannot be blue without replacing the iron ion, although this claim is challenged by references to other organisms like horseshoe crabs.
  • There is a suggestion that the misconception may stem from the appearance of veins through the skin, which can appear blue.
  • Some participants propose that the sibling might believe deoxygenated blood is blue and that it turns red upon exposure to oxygen.
  • A few participants humorously suggest extreme methods to convince the sibling, such as drawing blood or witnessing animal slaughter.
  • Concerns are raised about the sibling's understanding of blood color and whether color blindness could be a factor in the misconception.

Areas of Agreement / Disagreement

Participants express a range of views on how to address the misconception, with no clear consensus on the best method or explanation. Disagreements arise regarding the biological claims about blood color and the implications of different blood components.

Contextual Notes

Some claims about blood color depend on specific biological contexts and definitions, such as the distinction between oxygenated and deoxygenated blood. The discussion also touches on the complexity of color perception and the influence of external factors.

  • #31
DaveC426913 said:
Lower pressure of what? Syringe reservoir starts off at zero volume (because plunger is fully inserted). Pull back on plunger, syringe fills with blood. Where would the air come from?

There's still some air in the needle. You got to create a perfect vacuum. It just takes one oxygen atom to change an entire sample of blood from blue to red.
 
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  • #32
Regardless though even if you had veinous blood out in the open air and you had arterial blood you wuold notice they are different in colour.
 
  • #33
leroyjenkens said:
There's still some air in the needle. You got to create a perfect vacuum. It just takes one oxygen atom to change an entire sample of blood from blue to red.

No need for vacuum - fill the syringe first with water to make sure there are no air bubbles left.
 
  • #34
Borek said:
No need for vacuum - fill the syringe first with water to make sure there are no air bubbles left.

How about oxygen in the water?

Also, what if clotting changes the colour of deoxygenated blood?
 
  • #35
atyy said:
How about oxygen in the water?

Also, what if clotting changes the colour of deoxygenated blood?

What if you have no evidence to support your theories? What if you just keep posting for the sake of posting?


Answer: You go to the principals office.
 
  • #36
zomgwtf said:
What if you have no evidence to support your theories? What if you just keep posting for the sake of posting?


Answer: You go to the principals office.

Please provide a refereed reference that shows the measurement of the colour of non-clotted deoxygenated blood, stating the level of deoxygenation of the blood.
 
  • #37
atyy said:
Please provide a refereed reference that shows the measurement of the colour of non-clotted deoxygenated blood, stating the level of deoxygenation of the blood.

Who ARE you and where are YOUR references. All I see you doing is making claims that because Iron sulfate is greenish blue that it means that porphyrin in our blood doesn't make our blood red. YOU need to substantiate what your saying about de-oxygenated blood having an effect. This will go on forever if you just keep making up scenarios and requesting evidence oh-contrare.
 
  • #39
Sorry, other than the OP's brother, is there any serious dissent that oxygenated blood is bright red and deoxygenated blood is darker red?

If not, are we arguing for the sake of anything more than because we like the sound of our own voices?
 
  • #40
DaveC426913 said:
Sorry, other than the OP's brother, is there any serious dissent that oxygenated blood is bright red and deoxygenated blood is darker red?

If not, are we arguing for the sake of anything more than because we like the sound of our own voices?

See the two references in post #38, and http://omlc.ogi.edu/spectra/hemoglobin/ .

I would guess:
Is hemoglobin blue? No, it has a huge absorption peak in the blue.
Is deoxyhemoglobin bluer than oxyhemoglobin? Yes, it has a larger absorption peak in the red.
 
  • #41
This is all pointless. The question is asked and answered. Thread locked.
 

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