That definitely helps me grasp the idea that really we're trying to apply the closest concepts that we have, but that they're sort of just touchstones to use as you work to understand the full picture. ...Of course on some level that's true of how we understand most things in science, you work with what's good enough until it isn't any more.

...Well, it's helpful to be reminded that EM fields aren't necessarily changing their properties over time, at least

...whoops

It's certainly helpful. I have started to "get" somewhere along the way that EM waves are oscillating in 3D space and therefore the typical 2D squiggly line isn't sufficient, and that photons are somehow more like an intersecting point.

Thanks a lot for this reply. I've definitely started recognizing what you're trying to say in those other posts, that things really approach a point where you need to trust the math and coming at it the other way around fails to create an accurate understanding of things. (And that our intuitive understanding of what "stuff" is doesn't really hold water in an absolute sense).

I think I'm coming out of this with a less incorrect "mode C" mental model, at least– EM fields change over time / distance (one in the same in this case but whatever) in a cyclical way, so they're waves. We can measure how long it takes for one "wave cycle" to happen, as in the distance traveled as a point oscillates between the electo- part and the -magnetism part. ...Which is certainly still a pretty wrongheaded explanation and I really need to start learning the math of physics in my spare time.

That does make more sense.

u/shikuto's comment got me to sort of picture how EM fields are waves (they're traveling through space as they oscillate, after all, which is all a wave is), but it's still surprising to me to say that the change in polarity is actually a locational change, if that's what you're saying.