What fact were you taught in high school that you later learned was completely untrue?

All of the chemistry, about three times.

Electrons are little balls that circle around the nucleus.

Just kidding, electrons move in these little clouds around a nucleus.

Just kidding.

Electrons move in these different hybrid clouds.

Just kidding. Electrons hybrid clouds. Just kidding.

Electrons are clouds.

Just kidding.

F-U.

Also, light only moves in straight lines except when it doesn't.

Our gym teacher told us your body temperature increases by 40 degrees when you run.

When we pointed out, you go to the hospital with a fever of 103,

she told us it was different and to stop acting smug. That's why she teaches gym. Maybe she

confused temperature and heart rate? The sun is half star, half planet. I had a middle school

teacher who told us that Buddhists have to pray to Buddha three

times a day. Took me until high school before I realized he was probably thinking about Judaism.

You can't take a bigger number away from a smaller number? Oh my God, yes. I remembered when we

learned about negative numbers. I was so gosh darn teed off and upset. Nowadays, I tutor young kids,

and when this question comes up, I will take the time to try and explain it in a very simple

way that won't cloud or confuse them. One time, though, a kid got excited about what he learned

and showed it to a friend and came back to me next week and said his teacher said I was wrong

...