Student100 said:
https://www.amazon.com/dp/0199540284/?tag=pfamazon01-20
Was the prevailing view on natural philosophy for over a thousand years, and well worth reading for anyone serious about studying the philosophy of nature.
https://www.amazon.com/dp/0521564832/?tag=pfamazon01-20
Bacon is one of heroes, and doesn't receive enough attention in history classes because he's shadowed by Galileo. This is an interesting read and one of my favorites in natural philosophy.
Dancing Wi Lu Masters is pure garbage. It is neither natural philosophy, philosophy, nor any such thing. Just so you know.
Generally agree. (Haven't read Campbell. Probably would agree if I did.) These do however deal with old and in fact outdated material and youngsters might not like to wade through it all. This is not to denigrate it and is a matter of taste for the reader. It is more important that the youngster read varied material eagerly than that s/he begin at the beginning of philosophy and work through to modernity, which can be very tedious and off-putting. (Off-putting is the killer!)
That said, at
https://archive.org/details/texts there is a huge lot of out-of-copyright material, including Bacon, Aristotle, and all the pioneer philosophers and scientists, the likes of Tyndall, Darwin, Maxwell, Faraday, Fabre, Boole, de Morgan, Dodgson(Carroll) free for download in multiple formats for which there are free readers available (PDF, DJVU etc) and don't forget Project Gutenberg at
http://www.gutenberg.org/ebooks/
If you want quite a lot of excellent modern material, and can afford it, there is a great deal, and one of the main problems is that in-copyright out-of-print works can be VERY hard to obtain.
It is not clear what the level of your niece's studies might be, whether we are talking late primary school, high school, university, or even post graduate work, so it is hard to know what would be over-stressing her and what would insult her intelligence, or even what her lines of interest within physics might be. A fascinating work is "Physics from Fisher Information" by Roy Frieden, but if she is not yet comfortable with differential equations, it would be dangerously opaque. The collected Scientific American works of Martin Gardner are available on a CD, and they broach a lot of non-trivial physical and variously edifying and entertaining philosophical material. Carl Sagan's works include some seriously good stuff and so do those of Richard Feynman. Ilya Prigogine and Stenger's book "Order out of Chaos" is pretty special. "The Mind's Eye" by Hofstadter and Dennett is a real mind-bender for ANYONE, and so is "Goedel Escher Bach". Try the Smullyan books such as "What is the Name of This Book" (wich is beyond Joe Average, but I have personally known two kids about 8 years old to DEVOUR it.
Two books, one great in my opinion, the other very good indeed are "Structures, or Why Things Don't Fall Down" by JE Gordon, and "Cats' Paws and Catapults" by Vogel. Don't neglect books by Stephen Pinker such as "The Langauge Instinct" in particular. Some straddle the subject of information theory, Physics and biology, such as John Maynard Smith and Eors Szathmary (The major Transitions in Evolution"
I'll stop here for now, but I am sure you will be welcome to rattle cages. Good luck to you nad your niece.