Life-relevant Salvage from School

School is mostly useless but not entirely, completely useless. I enjoyed the hour we spent on cold and warm fronts.
The relevant wikipedia pages have handy-dandy charts. Though of course my school, being longer ago, had diagrams, and wikipedia doesn't.
https://en.wikipedia.org/wiki/Cold_front
https://en.wikipedia.org/wiki/Warm_front

I remember the picture we had, though often not which is which. The main thing is that cold fronts are sharp and steep, while warm fronts are slow and gently sloping. 

Cold is dense and heavy and can easily bully the warm air out of the way. It gets under the warm air a bit and then kind of bulldozes it. Due to being shoved sharply upward, the warm air cools and tends to form a sudden, intense shower. Basically the cold is wringing out the warm sponge.

Warm air is light and struggles to move the cold air, even with sheer mass. It kind of rides up on the cold air and then presses down, forcing the cold air to ooze out from under it. The warm air behind shoves the vanguard air up the slope, which then forms gentle spitting rain that lasts for hours. Even fog in in extreme cases, when the clouds descend so far they touch the ground. 

The question is whether these little bits of applicable knowledge got in by mistake or by oversight. Did they mistakenly think it was properly irrelevant? Did someone sneak in under the radar? Did someone get lost, buy the myths about school, and unknowingly break the rules? Most curious.

This knowledge isn't actionable, as the buzzword goes, but it is at least something that affects you directly. You can look at something that happens to you, then understand what's going on beyond the brute obvious. 

You can call it slightly actionable if your hobby is predicting the weather using your eyes and nose instead of the subsidized forecasts.