this post was submitted on 13 Oct 2025
1276 points (99.5% liked)
People Twitter
8369 readers
1083 users here now
People tweeting stuff. We allow tweets from anyone.
RULES:
- Mark NSFW content.
- No doxxing people.
- Must be a pic of the tweet or similar. No direct links to the tweet.
- No bullying or international politcs
- Be excellent to each other.
- Provide an archived link to the tweet (or similar) being shown if it's a major figure or a politician. Archive.is the best way.
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
My 4th grade science teacher genuinely taught us that "blood is blue before it leaves your body and turns red due to oxidation from contacting the air"
Even as a kid I thought that was stupid. If blood is blue in the body and only turns red when it touches oxygen, then why is it red in the water?
I was told that's only in the movies. In real life it would be blue.
But then again I got a detention for arguing that the moon is visible during the day. The detention was because I pointed out to the window and said look, and she was embarrassed.
Because there's oxygen in water. That's what fish breathe!
The answer is obvious, dissolved oxygen in the water--duh!
Ohh yes, classic detention for proving the teacher wrong. There’s a depressing amount of teachers who rule by their ego instead of by science. It’s why I now consider my school discipline record as a source of pride instead of shame.
One if my brothers teachers sent over half of her class to detention one day and the vice principal brought them all back like "you cant just send your whole class, get a grip"
That's wild to me cos like... We didn't need internet to tell us this was incorrect.
It's not like it doesn't have some logic to it. Blood carries oxygen throughout the body and then cycles back through the lungs to get more oxygen. So when you look at your arms and see the blue veins we just thought that was obviously the deoxygenated blood returning to the heart.
It made basic sense, so no one was running down to the library to check out a medical textbook to disprove it.
Ever see a blood draw? Blood comes out of a vein, into a non-O2 environment.
I think we just don't do as much critical introspection as we like to think. Its easier to imagine maybe there was a tiny amount of O2 or something than that the thing we were taught was entirely false.
It's definitely true, and it shows that the stuff you learn as kids is even more ingrained than we even notice most of the time. Kids don't normally have blood drawn, so it's not like elementary schools were filled with a bunch of kids saying "wait a minute, that didn't happen with my last blood draw."
There were actually about 5 of us that contested it and she tried to say "they drew that blood from your arteries"
You look when they draw blood?
Yes. Its neat. You dont?
My first thought was how ears and noses look red when sunlight shines through them. If blood was blue, wouldn't they be blue or purple?
Veins appear blue because the skin and veins refract the light to permeating the skin causing the wavelenths to appear blue. It was well known in the early 2000s. She was just stupid and had no business teaching science.
We had the internet and a handful of us tried to contest it. She said "look at your textbooks, they clearly drew that blood from your arteries"