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People really should know the difference between sci fi and fantasy. More than half of these books are fantasy.

Sorry, nevermind I thought it just said sci fi ya novels. My bad.

if you like fantasy novels vote on the list - best fantasy books for pre-teens and children

Agreed! This is not a good sci fi list. For people who would like to differentiate:

FANTASY:
World building
Use of magical abilities
Heroic quests or adventures
Moral absolutes: good and evil

vs. SCIENCE FICTION (which shares SOME characteristics but definitely not all!)
World building
Use of technology
Space travel
Alien encounters
Expansionist viewpoint
Contemplation of ethics

And then there are subgenres, such as dystopia, which qualify as sci fi but with some big differences:

Much or even most science fiction is hopeful, positive, and broadening in its view of people in the world (or worlds). The focus of science fiction, even though fraught with problems, is a positive, problem-solving one. It’s people being hopeful about the future manifestation of a better, or at least a different, life.

On the other hand, most dystopian fiction is dark, negative, and limiting in its world view. That’s not to say there aren’t redeeming moments in dystopian fiction, because there are; but they take place from within a world that deliberately tries to squash that kind of thinking, while sci-fi is all about the expansion—of thought, of inventions, of the human place in the universe. Dystopian and post-apocalyptic fiction is about taking what little you are left with after whatever happened—either to you personally and/or to your world—and trying to make it work.