In terms of YouTube videos/channels, Crash Course has some pretty good introductory stuff in several fields. Might also be cool to find some reading related to what you're learning about. It could be a book or article (for example, NPR's climate solutions week) but, depending on age/level, you might also find scientific papers. New research tends to be ultra-specific and technical, but if you can find a review paper (which basically summarizes the existing body of knowledge on a given field), those can be a bit easier of a read. One note on the scientific papers/articles: I would recommend seeing what you have access to via your library. Some research databases are expensive for individuals but some organizations can give access (for example, the Arizona State Library has this (link:
https://azlibrary.gov/dazl/online-reference_ online reference). Could try having a "journal club" where you all read/learn about something and come back together to discuss what you learned both as a means of learning and to gauge everyone's progress. In terms of note-taking, you probably want to make sure they are taking good notes. Note-taking is a skill and if you are learning through taking notes, you need to be taking good notes. Might also look at state standards for science or any other subject just to make sure they are getting enough instruction. They have specific learning goals for each age (ex: graduating kindergarteners should be able to count to 100).