Atomic theory, nuclear fusion, spectral lines, all of that explained with language that is both interesting and understandable for a child. Yes, it is possible.
The book's editors didn't trust young children to understand this, so they listed 12-15 years as age recommendation..
Sometimes I wonder how people come up with these age recommendations and whether they read the books first. The other book we read recently was Beechwood Bunny Tales by Geneviève Huriet. The Russian version of this book has "below 3 years" as age recommendation. Maybe they reached this conclusion by looking at the pictures?
One of the first Mastodon instances, there is no specific topic we're into, just enjoy your time!