What makes 幻想 different from Sci-Fi?

I doubt wizards, witches, ghosts, goblins, dragons, and demigods have anything to do with science.

Boom.

Sci-fi is 更多 about the future with future technology.

幻想 is 更多 about ancient creatures and legends and doesn't have to be in the future. Also 幻想 has nothing to do with humans and their advanced technology.

Sci-Fi,as 你 might know,has to do with science,something that was caused/created 由 science.
'Harry Potter' is fantasy,their's no science behind it 或者 in it,except Potions class,which is known as Chemistry.
'The Hobbit' is 幻想 as well,no science behind it 或者 in it.
幻想 is usually made up.I mean,a completely different world,fairies,wizards,witches,mermaids,goblins,dwarfs,and hobbits aren't real,most commonly found in 幻想 stories.
'The Walking Dead' is a sci-fi based TV/comic book series.Zombies are created from science. A lab gone wrong,deadly disease,causing tons to die the return from the dead as flesh-eating,disease carrying zombies.Sci-fi can also be something that seems futuristic,like cylons,robot's,flying cars.
'Halo Reach' is the perfect example of a Sci-fi video games.Ther perfect combo of aliens,zombies,drama,Spartans,and science,all crammed into one amazing,adreniline pumping,addictive first-person-shooter.

well my best guess would be is 幻想 will be all of mythical creatures and magic used where scifi would be use of machines and aliens of course when some of these have magic and machines its hard to know what it is

boh i don't know

Simply what makes magic different from science. One is rational, explainable, and possible to the skeptic mind of this world; the other is irrational, unexplainable, and impossible for the skeptic mind to fathom.

Sci-Fi means something fictional can be backed 由 science. It can also mean a scientific prediction of the future in 图书 like The Hunger Games. Fantasy, however, is all fiction and can't be backed 由 science.

*pulls out 星, 星级 Wars book and looks through it for any mention of fairies, dragons, 或者 magic* Nope. *pulls out Inheritance and looks through it for any mention of R2D2 或者 Data* Nope.