Science is grounded in the concept that we, as humans, can examine and understand the world around us. This is practically one of the roots of humanism as a philosophy. We don’t need supernatural causes to explain our surroundings. As Douglas Adams said, or perhaps wrote, “Isn’t it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?”
In fact, the supernatural and science don’t play well together. A natural world can be studied, examined, and perhaps most importantly, quantified. We can’t be absolutely certain that a result from an experiment is a good representation of reality, but the better designed an experiment is, the closer to 100% we can get. Hence, the incredible excitement from particle physicists that a candidate for the Higg’s boson had been found and that the statistics showed that their results were valid to five sigma (five standard deviations). The scientific method would not work if capricious sprites and malevolent gremlins were playing in the results.
To put it simply, if you don’t start out with the concept that a human can understand the world through human endeavor, science would be a waste of time.
Science is often criticized by many religious or spiritual individuals for rejecting the supernatural, and is mired in a dull, naturalistic world. Again, the problem is that the supernatural, when we try to detect it, provides no good evidence that it is there. If it did, curiously, it would cease being supernatural and become natural.
Stephen J. Gould described this as non-overlapping magesteria (NOMA), wherein the natural and supernatural, the scientific and the religious, operated in two separate and distinct areas. Think of it like a Venn diagram, where the two circles don’t overlap. Sadly, this isn’t exactly a good explanation of how religion and science intersect. Instead, I prefer my own mental model of mutually exclusive magesteria (MEMA).
In the classroom, it is by far best for a teacher to rely on the NOMA model. Avoid getting yourself into a position where you support one religion over another, or your interpretation of religion over another. Just rely on what the evidence is and know that there are organizations that will back you up if you come up on a group that wants to pick a fight over evolution, stem cells or climate change.
However, where science has looked, the supernatural has given way. Many religions and denominations of religions accept this and shroud their position in mystery, holding to claims that they have answers to different kinds of questions. Others refuse to accept the evidence that they are wrong, and refuse to adapt. Failure to adapt to a changing environment tends to be the first step on a path to extinction.
The Earth is not the center of the universe. Zeus/Thor/Baal does not throw lightning from Olympus/Asgard/Bali Hai (that last one was a joke). Humans are primates, vertebrates and mammals. Humans can understand the world without resorting to ad hoc or post hoc claims of the supernatural.
There are no fairies at the bottom of the garden, but the garden is just as wonderful a place.