Not that long ago, I had a kid ask me what my favorite thing about science was. I had to think about it for a minute. I mean, it's not an easy question. Science put humans on the moon and has shown us the depths of time and space. With a little applied chemistry, you can create all sorts of spectacular and safe (for us professionals, anyway) pyrotechnics. Hell, science gave us the technology to create Fallout 3.
After consideration, though, I gave him the answer "My favorite thing about science is that, when I think like a scientist, I'm better at knowing true things from false things." That may seem self-explanatory, but I think it bears a bit of unpacking.
Science isn't just a body of knowledge or a list of cool facts. At its core science is a method. A group of methods, really, that varies depending on what kinds of questions you're asking. There are the double-blind, randomized controlled trials of psychology and medicine, the enormous particle colliders in which theoretical physics hypotheses are tested, and even the carefully neutral participant observation of a cultural anthropologist. What these methods, collectively called "science," generate is a body of knowledge, which is generally called "science."
These methods are all, at their core, different ways of controlling our observations about the universe in which we live so we can gather high-quality evidence that leads us to conclusions about its nature. This means that we're always learning more, becoming more accurate and refined in our understanding of the universe and everything in it, from distant galaxies to the way the human brain works. This also means that sometimes we learn something new that contradicts something old. This isn't a problem in science; in fact, it's what we want to happen. Old ideas can be flat-out wrong (Earth is the center of the universe) or they can be mostly right but fall apart under certain circumstances (Newton's laws).
The search for understanding means that we have to be willing to modify or even completely jettison old ideas when new ideas, with strong scientific evidence to support them, point to a flaw in them. In science it is not just okay, but encouraged, to be able to say "I was wrong" if new, contradictory evidence comes to light. Science's greatest strength is that it is self-correcting; bad ideas will eventually out themselves as our understanding progresses.
This is key: if we had ignored Einstein's theories of relativity because Newton's Laws were old and well tested and, well, Newton was pretty damn smart, we wouldn't be able to use GPS technology. The gravitational difference between the surface of the Earth and the distances at which GPS satellites orbit, predicted and explained by general relativity theory, means that there is a difference in the relative passage of time between us and any of those satellites. Had we rejected Einstein we couldn't take that difference into account and GPS would be difficult if not impossible to implement.
And yet it goes even further than that. Einstein once lamented that due to his contempt for scientific authority in his youth, fate had made him an authority in his maturity. When he was older, he pushed back against the new theories of quantum mechanics, famously saying that "God does not play dice with the universe." And yet quantum mechanics, as weird and counterintuitive as it is, was a yet further refinement of our understanding of the universe. Had we crowned Einstein a New Authority in place of Newton and, on his word, ignored QM, we wouldn't have superconductors, which means we wouldn't have transistors, which means we wouldn't have computers or Fallout 3.
Science, strictly speaking, isn't in the business of what philosophers might think of as "Capital T Truth." Rather, science, as a discipline, aims to discover the facts of the matter, whatever that matter is, by gathering evidence. Since science is always open to correction, I think of it as a progressive, concerted effort to become less wrong in how we think about the universe. And by watching my biases, basing my beliefs on evidence gathered with solid methodology, and being open to being wrong, I can think like a scientist and make sure that I am also continually retreating from false ideas in the pursuit of true ones.
But the best part is that you can do it, too.