This week, a Reddit thread asked users, "What is the most hilariously incorrect thing a teacher told your class?"
The thread quickly went viral, as more and more people started sharing the ridiculous — and totally, patently false — things they learned in school. As it turns out, some teachers believe things that are absolutely wild.
Here are some of the funniest (and most alarming) responses:
1. "Computer teacher told us if you select 'cut' on an image from a website it will be removed from the website and will upset the website maker, so we had to use 'copy.'"
2. "While teaching Japanese history, my teacher was entirely convinced that the suicide of a Japanese samurai was called 'sudoku,' instead of 'seppuku.'"
3. "If you jump up and down after sex, then it will kill the sperm and you can't get pregnant."
4. "If a bug was in an airplane it would not be able to fly forward because it could not fly faster than the plane was moving."
5. "My grade 6 teacher told me that 'fatigued' was in fact not a word when I used it in a short story and insisted that I looked in the dictionary. Found it and proved her wrong in front of the whole class."
6. "That a Big Mac from McDonald's overwhelms your stomach with so much of everything that it doesn’t register you’ve eaten anything and that’s why you get hungry again so quickly after."
7. "Our teacher put materials from plants and materials from animals on a board. We could not convince her that wool was not a plant."
8. "I had a teacher who swore that the Underground Railroad was a physical railroad that ran under the ground."
9. "That dogs evolved longer faces so they could smell things around corners."
10. "She showed us the flag of the United Kingdom and said, 'This is the flag of America.'"
11. "Once a horse closes its mouth, its jaw locks and it is literally impossible for a human to open its mouth again."
12. "We were told to 'sodomize' instead of 'cauterize' the wound."
13. "I once had a math sub that told our class that any fraction that was over 1 equals 0."
14. "A person with conjunctivitis can spread it just by looking at you."
15. "A teacher of mine told us that the left side of your body is your feminine side, the right side is your masculine side. That's why your skin is better on your left, your right is stronger, etc. What the hell?"
16. "Last year a biology teacher told me that the T. rex was only 180 centimeters tall and had wings."
17. "My economics teacher said that simple interest and compound interest were the same thing. I spoke up about it in class and she took me into the hallway and told me not to disagree with her again."
18. "How to count by twos: 2, 12, 22, 32..."
19. "My science teacher, during the sex ed portion of the year, said all penises are the same size 'when it counts' (i.e. when erect)."
20. "All lights are outfitted with cameras for the government, so we shouldn't use them."
21. "If you make more money you get taxed at a higher rate, so overall you lose money with a promotion. This was my economics teacher in high school."
22. "That the moon is just another star like the sun."
23. "Mrs. Stanford in my 8th grade history class told us that 'People invented sleep because they were bored.'"
Note: Some responses have been edited for length or clarity.