Hi, my name is David Schultz and this is Our Earth: Its Climate History and Processes. This lecture is about how science works and you may be already familiar with how science works by reading newspaper articles about scientific discoveries. You may read popular science magazines or you may even have a friend or colleague who is a scientist and does science. But for the purposes of this course, there's one thing that I really want to emphasize and that is we're not only going to learn what it is about the Earth, its climate history and processes, but I want you to understand how we have come to learn this, because I think that's the most interesting part of being a scientist is not just learning the facts but also discovering how these facts were discovered. So with that, we need to start with the way that people think science works. Usually, when we talk about how science works, one of the things that comes up is the scientific method, and the scientific method has several different steps to it. A scientist may have a question about something about the way the earth works and so they ask this question, they propose a hypothesis, they take an educated guess about how what might be going on, then they go out, they collect data, they may run a computer simulation, or they may take some kind of observations about the way the earth works. When they've collected this data, they analyze it and see if it fits their proposed hypothesis, and then, finally, they can draw a conclusion and then communicate those results to other people. This is usually the way that science is described to other people, but not all scientific discoveries actually happen this way. Sometimes they're serendipitous, sometimes it's just the weight of accumulated evidence is enough to overturn previously thought of concepts about the way the Earth works. So, I really want you to appreciate this, that the scientific method isn't always the way that we do science. Science also isn't all known; there's still a lot of things that we don't know and that's what makes my job and other scientists job very interesting. We're out there trying to discover new things about the way the Earth works. So as a result, science is evolving. What we knew 10 years ago or 20 years ago is not what we know about the Earth now, which means that textbooks, which are a snapshot of someone's idea of the way that science works, isn't necessarily the right way, that science may evolve and it's only one person's perception. But, generally, the textbooks try to synthesize the work of many scientists and come together to produce the most accurate and up to date information. But, as I said, this information can go out of date. One of the ways that this information goes out of date is by the scientific literature, the peer reviewed journal articles and other scientific presentations that we, as scientists, do when we go to conferences. The problem is that even this scientific literature isn't necessarily the truth. Just because the work is published doesn't necessarily mean that it is correct. It needs to be verified and tested by other scientists as well. Another thing that I want to convey to you is the difference between a hypothesis and a theory. A hypothesis is an explanation of the observations based on physical principles, based on the best scientific evidence that we have at this time. A theory, on the other hand, is a hypothesis that has survived repeated testing and, as far as science goes, it's the closest that we can come to the truth. So, we need to distinguish between something is Smith's hypothesis, either his or her best guess about the way we think science works versus something like the theory of evolution or gravity or even relativity. These are well-tested ideas and have held up to repeated scrutiny. So, in colloquial conversations among ourselves, we may use the word hypothesis and theory interchangeably but, as scientists, we make it very clear the difference between a hypothesis and a theory. So to wrap up this lecture, first, I really want you to get out of this course how we know what we know, as well as the facts of what it is that causes the Earth to operate the way it does. The other thing is the scientific method isn't the only way that we arrive at new scientific discoveries. That science evolves, the information that we knew at one time may not necessarily hold for all time. And then, finally, I want to emphasize that, as scientists, we make it very clear the distinction between hypothesis and theory. Thanks for watching and I'll see you in the next video.
