Things you learned in school that are no longer true.

[Jacob]

It's kinda overpowered to get supremacy AND invisibility. It would be seriously unbalanced to have both.

[Admiral Yi]

You posts here suggest otherwise. 

That's because you, like most inhabitants of the political extreme, are a Manichean, and unable to see any issue except in terms of black and white, good and evil.

[mongers]

Eek, we seemed to have somewhat derailed Raz's thread.

[mongers]

You posts here suggest otherwise. 

That's because you, like most inhabitants of the political extreme, are a Manichean, and unable to see any issue except in terms of black and white, good and evil.

I take it back, I'm not sure you're interested in the good social consequences of individuals 'selfish' actions.

[Duque de Bragança]

Learning about the USSR compared to the US, in the early '90s, during the geography classes. Geography teacher was also the history teacher as always in France in high school.

[Josquius]

I recall a book I was given as a kid contained a large entity dominating a huge chunk of Eurasia called the CIS.

[Valmy]

Learning about the USSR compared to the US, in the early '90s, during the geography classes. Geography teacher was also the history teacher as always in France in high school.

We must have looked pretty good in that comparison

[garbon]

There seems to be a discrepancy between thread title and OP. Many of the items noted so far seem to satisfy thread title but not OP as they were once true but are not true anymore and hence not taught whereas OP talks about things that were once taught either because they were then thought to be true / or the result of a teacher perniciously providing false information.

[Liep]

I had a Danish teacher who told me God was real.

[Duque de Bragança]

Learning about the USSR compared to the US, in the early '90s, during the geography classes. Geography teacher was also the history teacher as always in France in high school.

We must have looked pretty good in that comparison

Geography textbook said the US had really conquered and mastered its space, while the Soviets facing harsher contraints did not manage to do so, or only partially.

[Valmy]

I had a Danish teacher who told me God was real.

Well it hasn't been disproven

[garbon]

On the side of "pernicious misinformation" though I suppose not really pernicious is how in physics & chem they would teach you in intro classes how to calculate various interesting things. When you took later year courses, they would point out how the simple formulas they made you learn don't actually describe the actual phenomena.

[Duque de Bragança]

At uni, I had a class on audio-visual technology, where I had to learnt by heart a thick dossier on camera, film, TV, audio... tech of the late 1990s. I got an A+. All of that technology is now completely obsolete.

Yeah I used to be a video technician and all of that knowledge is redundant.  Maybe the telecine work would be somewhat relevant,

Blu-rays are still made from telecines. Of course, no digital intermediate in your time.

but since that was all mastered onto u-matic (?) maybe not.

Obviously not. Except for '70s or '80s sources that need to be archived.

[frunk]

On the side of "pernicious misinformation" though I suppose not really pernicious is how in physics & chem they would teach you in intro classes how to calculate various interesting things. When you took later year courses, they would point out how the simple formulas they made you learn don't actually describe the actual phenomena.

Q: How does a physicist milk a cow?
A: Well, first let us consider a spherical cow...

[Razgovory]

I remember arguing with the sociology teacher that homosexuality was primarily an inborn trait.  He told me I was wrong and to shut up.  I even sited sources.