I'm guessing that by "assumed knowledge" you mean things that are memorized, or not observable, things that you could not verify by your own direct experience. Even now, after getting a Ph.D. in a science-related field, large portions of science falls under the "assumed knowledge" category for me. This includes many ideas that I have used along the way. Many things must be taken as givens because you don't have many lifetimes to replicate every single experiment on your own and you can't spend the one life you have on reinventing the wheel.
One thing I liked about physics, is that we actually did experiments to verify the mass and charge of the electron. Detailed understanding of how electron diffraction could yield complex crystal information seemed like quite a reach, and anything beyond that was just too much of a leap of faith. For that reason, I didn't go into chemistry as my undergrad major or for my Ph.D.
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A boy and his dog can go walking
A boy and his dog sometimes talk to each other
A boy and a dog can be happy sitting down in the woods on a log
But a dog knows his boy can go wrong