to think deoxygenated blood is blue?

[MountainMert]

So, I know blood is red but...
When I was at school, on diagrams, the oxygenated blood was coloured in blue to show it was oxygenated and the deoxygenated blood was red. This made sense to me because there's oxygen in water and water's blue.
DH is a science teacher and he's just told me that the diagrams now are the other way around. Oxygenated blood is red and deoxygenated is blue. This makes no sense to me.
Am I imagining that it was the other way around or did they change it?

I'm 99.9% sure that water is actually blue

I am 99.9% sure that you are not a science grad

I’ve never seen any other way of depicting blood as red=oxygenated, blue= deoxygenated, Op, and I’ve got a little collection of old medical textbooks dating back to early 1900’s. The attached picture is from a book published in the 1941.

Arteries leave the heart and are carrying oxygenated blood = red
Veins go to the heart, carrying deoxygenated blood = blue
EXCEPT for pulmonary artery (deoxygenated, going from heart to lungs) = blue, and pulmonary vein ( oxygenated, going from lungs to heart) = red.
Are you just remembering the pulmonary colours? These were the exception to the rule.

I remember my GCSE biology textbook in the late 80s and deoxygenated blood was colored blue for diagrams but I didn't think it was blue just that it was colluded blue to show difference in direction of travel. It was a long time ago now though..

This made sense to me because there's oxygen in water and water's blue.

There's oxygen in all living things but most of them aren't blue. There's oxygen in rust and it's red. Water is blue but not because of the oxygen (for the PP who thinks it's because it reflects the size look at an inside swimming pool or even a filled bath. Water is very lightly blue.

Defo deox which was blue. Because I got confused by the explanation (I have only just realised what the teacher must have actually been trying to explain though, so thank you!) and thought for a while that blood actually was blue until it met oxygen, and that's why veins look blue through your skin.

Later I realised this was rubbish, but just thought that whichever teacher said that in the first place must have been talking rubbish. Not that diagrams differentiate between oxygenated and deoxygenated.

I did actually know that blood gets oxygen from the lungs and I was quite good at science so am a bit that I was confused about this!

@DueNumberTwo

Oxygenated was always red on the diagrams and deoxygenated was blue.

And obviously water is clear (although I'm sure you were joking?)

According to Google, water is blue.

Seen plenty of people bleeding out and never seen blue blood. It's darker. That's it.

Cheese and onion crisps were in green packs before Walkers took over as majority provider from Golden Wonder.

Your veins look blue through your skin, but the blood inside is definitely not blue, just a darker red. Very deoxygenated blood can be almost black, but definitely not blue!

Water is blue, intrinsically, but when you look at the ocean or a lake the colour is mostly determined by what it’s reflecting (usually the sky).

Why then do patients look blue when their oxygen saturation levels are low?

As someone with a science background Oxygenated blood is red deoxygenated blood is blue

Blue blood goes from the heart to the lungs turns red, red blood goes back to the heart then goes around the body

Not the best of diagrams IMO but this sort of explains it

Water is blue - or other colours - https://www.usgs.gov/special-topic/water-science-school/science/water-color?qt-sciencecenterrobjects=0#qt-sciencecenterrobjects

You have it the wrong way round.
Do you have blue water coming out of your tap? I wouldn't drink that if I were you.

It’s 2020 and people still think water is blue because it reflects the sky 🤦‍♀️

Oxygenated blood is red, deoxygenated is blue. Because our veins are blue

To clarify (again!) - I know that blood is red. I am ONLY referring to the diagrams. Jesus Christ.

• I understand the circulatory system
• I understand what blood is
• I understand what oxygen is

I misremembered which way around the blood was coloured on diagrams!

And, yes, water is blue.

@Bluetrews25 is completely right. the diagrams have been that way since at least the late 1970s

But of course, if the world ended in 2012 and we are now in the entropy universe, you are probably simply from a different uni/multiverse (or something)

People who are hypoxic turn cyanotic.
Cyan is blue.

[quote ChristmasFluff]@Bluetrews25 is completely right. the diagrams have been that way since at least the late 1970s

But of course, if the world ended in 2012 and we are now in the entropy universe, you are probably simply from a different uni/multiverse (or something)[/quote]
This is a good suggestion tbh. Either way, exams were too cheap to print in colour anyway so it didn't make any difference to my grade haha.

And, yes, water is blue

Do you know why it's blue?

@chomalungma

And, yes, water is blue

Do you know why it's blue?

Because it's easier to absorb longer wavelengths of light and blue is the shortest wavelength of light. (Imagine I said that like an adult instead of a five year old).

So what colour are deoxygenated cheese & onion crisps?