>I've always found it weird that you need teaching certification to teach basic concepts to kindergartners but not to teach calculus to adults.
There is a lot more on the plate when you are kindergarten teacher - as the kids needs a lot of supervision and teaching outside the "subject" matters, basic life skills, learning to socialize.
Conversely, at a university the students should generally handle their life without your supervision, you can trust that all of them are able to communicate and to understand most of what you communicate to them.
So the subject matter expertise in kidnergartens is how to teach stuff to kids. Its not about holding a fork, or to not pull someones hair. Just as the subject matter expertise in an university can be maths. You rarely have both, and I don't understand how you suggest people get both a phd in maths, do enough research to get to be a professor and at the same time get a degree in education?
I was an instructor for a college credit eligible certification course. While I think that education degree is more than you need, providing effective and engaging instruction is a skill and is part of actual teaching at any level. Concepts like asking a few related open ended, no right answer questions at the beginning of a new topic to prime students’ thinking about that topic. Asking specific students “knowledge check” or “summarize/restate this topic” questions throughout keeps students from checking out. Alternating instruction with application type exercises help solidify concepts. Lesson plans/exercises/projects that build on each other and reincorporate previous topics. Consideration of how to assess students between testing and projects, for example a final vs a capstone project.
If you are just providing materials and testing, you aren’t actually teaching. Of course there are a ton of additional skills that go into childhood development, but just saying adults should figure it out and regurgitating material counts as “teaching” is BS.