I remember the series was one of the earliest English books I picked up as a kid. It was beyond the scope of my fellow elementary school classmates (score one for the public education system!), but I found it to be completely engrossing in scientific "detail". In fact, I think there's a book you can find in libraries/bookstores specifically addressing the quantum mechanics, etc. It's this one, I think:

https://www.amazon.ca/Science-Philip-Pullmans-Dark-Materials/dp/0375831460/

Definitely one of those children's series that can be enjoyed by adults.