Well, to people stating that SF is only determined by the fact that whatever occurs in it
must be scientifically explained, I ask this question: What if a magical sword's properties (enchanted?) in a fantasy story get explained in minute details showcasing a whole "science" (witchcraft?) as a part of the universe the story is in?
What if a writer decides to explain the science of Gandalf casting a fireball? (And it CAN be plausibly explained, if one tried hard enough. Of course, it would be nonexistent today, but theoretically it could be probably done).
So what would you call that genre then? Science-Fantasy?
?
"The Scroll of Minor Fireball Magic"
I'll tell you about making fireballs: there's an ointment made from a plant that only wise wizards know of, and it can be usually found deep in Fangorn forest, in underground caves and subterranean rivers. Since some of the flora there exhibits sentient qualities (the Ents), other plants also bear a gene which enhances sentience and is highly mutable. The plant that Gandalf uses is called Afiora, and it has lived for eons in symbiosis with photoelectric and electricity producing amphibious gymnotidae (eels) that, as the name suggests, can release electric shocks.
These micro-eels have shared a large part of their evolution with the plant Afiora, by laying their eggs in between the surface of the stalk of the Afiora and its roots. The egg-eals also possess some electric potential, and when in large concentrations they can act as a battery which makes the Afiora a sort of a lightning-rod, or an electric shocker. When a fish passes by to eat the baby-eels in their eggs, the tip of the Afiora (charged by the concentration of electricity near its roots and stalk) releases an electric shock that hurts the predator fish and thus protects the egg-eels. The soil and rocks on which Afiora grows are richly saturated with conductive metals and ore, thus making the Afiora electrically active. The millennial symbiosis resulted in Afiora's adaptation to the conduction and retention of electricity, making the plant almost always electrically charged in minute quantities.
Now, wizards like Gandalf harvest the older specimens of Afiora (being way more electrically active), and actually eat it, allowing the plant's chemicals to enter their system. They also make an ointment out of it, which they apply on their thumb and pinky fingers. This ointment increases the electrical output and surface skin electrical charge that every being has. Now, on the palm (everywhere between the thumb and the pinky) another ointment (paste) is applied - this one being from a special sort of pine, which produces an anti-freeze liquid to protect its parts in the freezing North of Middle Earth. The liquid, when appropriately processed and mixed with ethanol and other alcohols, is made into a paste, which then serves as an isolator between the electrically charged thumb and pinky. However, the paste has a property of constantly evaporating a very flammable gas, which is used to initiate the fireball.
So how's it made? Gandalf meets an enemy. The years of consuming Afiora, along with the electrically enhancing ointment on his thumb an pinky allow him to be in a electrically charged state when his body reacts to danger, he gets goose bumps, and he conscientiously enhances the effect even further, being trained in techniques like meditation and other stuff, which enable him to increase the electric potential of any part of his body by focusing his will upon it. Now, when he's "charged" his hand enough, he aims, and he almost connects his thumb and pinky, which results in an electrical flash between them. This in turn ignites the flammable gas evaporating from his palm, which in turn further ingites (in a split second) the paste itself, which results in a fireball. The pressure from the gas igniting follows the shape of Gandalf's palm, forming a roughly circular shaped fire orb, which again, suppressed by the gaseous reaction, launches this "fireball" against his opponent. It is only effective at close range though, and wizards use it to clear corridors of enemy troops or scare wild beasts off, while they gather some Afiora in the underground, dark, damp caves.
So, that's the science of making fireballs! I just made it up. I can call it "The Scroll of Minor Fireball Magic" and copyright it. He he.
EDIT: I did.
---
My point is that ALL stories have at least a little bit of "science" in it. If that "science" isn't concerned with very specialized areas like bio-chemo-phitology or some other unheard of -logy, it doesn't mean the story is automatically bad just because the author didn't bother to explain the micro-stages of an egg hatching, or something. If the process is relevant to the story's context (like a parasite invading the egg and releasing a virus which alters the egg's DNA thus mutating it into something else) now IF this process actually matters, then yes, it should be explained. But if it's just a chicken hatching an egg (even if it's on a spaceship!), why would it matter how the egg got hatched? It got hatched, a chick was born, and the story moved on. Maybe Tolkien would've provided some science of his about how the Palantirs work, but he cared more about the story and the journey of Frodo and the significance of the Ring etc.
And I know I'm generalizing, but I'm just sharing some analogies which could probably help better understand my ideas.