And the last part of the prelude that I want to talk about is the scientific method. So let's start with the definition of science. Science has two definitions. Science is a body of knowledge. For instance, if we're talking about minology, the study of minerals, that would be the science of minerals. and all of the collective knowledge with respect to minerals that have been gathered and interpreted over the last few hundred years of study. But science is also a process, a process that is used to acquire new information through observation, measurement, and experimentation. This process is probably what you learned as the scientific method. So there are two definitions and we're going to focus in today on that second definition of basically using science as this scientific method. Hopefully you've heard of the scientific method and maybe even know the steps. If you don't, don't worry. We're going to go through them today. The scientific method is used by all scientists today. Hopefully by all scientists today. And by using the scientific method, scientists are working to update or get rid of old, less accurate models and replace them with more accurate scientific models. The scientific method starts with raw observations which can lead to questions. For example, early biologists, they were looking at some modern and fossil reptile skeletons. And what they noticed with these reptile skeletons is that they appear to have a pair of openings, i.e. holes behind each of their eye orbits. So, they had a pair right behind their eye orbit and right above their eye orbit. And this is what's known as a raw observation. They've looked at modern, they've looked at fossil reptiles, and they all seem to have these two pairs of holes. So the next step is they might have to question, do all reptiles have these two pairs of holes behind their eyes? With continued observations, looking at more skeletons, the biologists would see that there are many species of reptiles that do have these two pairs of holes or openings in their skull. When humans see a pattern like reptiles have two pairs of holes between their eyes, this leads us into thinking about questions. Why? We as humans love patterns and we want to know why there is a pattern. So we can state this pattern that we see in raw observations formally as a hypothesis. A hypothesis is an educated statement that provides an explanation for a phenomena that is testable. That educated statement can be a formal statement based on observed patterns. Now there are two things I want to point out about a hypothesis in its definition and you can see what those two things are because they are underlined. First, a hypothesis must be an educated statement or an educated interpretation or analysis of our observations. For example, if we observe ocean water tastes salty, our hypothesis is not going to be ocean water tastes salty because it contains lots of dissolved sugar. That would be a bad hypothesis because we've all eaten sugar. We know what sugar tastes like and it is not salty. Plus, when you evaporate seawater, what's left behind? Salt crystals. So we need to make sure that our hypothesis are rooted in our educated knowledge about the subject matter or our observations. We don't want to throw out anything and hopes that it sticks. The other thing about a hypothesis is that it must be testable by science. Most things can be tested by science, but there are a few things that cannot be. This includes the validity of ghosts, spirits, vampires, werewolves, and those other mythical creatures. Now, I know you're all saying, "But what about the ghost hunting shows that show those ghosts or the evidence of finding ghosts?" Those shows, they're all fake. But I believe you. If you have seen a ghost, that's great for you. But if we were all to go to a haunted house, and I have spent the night in a haunted house, I never saw a ghost. Other people who have stayed there have seen a ghost. Does that prove or not prove that ghosts exist? Well, a hypothesis needs to be testable by everybody. So if I didn't see one and you did, we are getting two very conflicting data results. So because not everybody sees these spirits, they're just not testable by science. The other thing that is not testable are things based on personal subjective questions like chocolate ice cream is better than vanilla ice cream. You can never get 100% of people to ever agree on the best tasting ice cream. They're very personal. They're very subjective. Everybody has different taste buds. Never will you get a 100% result in one favor. And so we can't test those by science either. If we go back to my previous example of early biologist noticing reptile skeletons having two pairs of holes between their eye orbits, behind their eye orbits. An hypothesis in this case could be written as a formal statement of an observed pattern. The hypothesis would be all reptiles have two pairs of holes behind their eye orbits. That is based on observation. It is testable. Everyone can go and look at these skulls to see if they can find the two pairs of holes. But remember not all perceived patterns are real or explanations to the obser observations are accurate. So we need to test our hypothesis. We refer to this as submitting to its falsification or subjecting the hypothesis to some evaluation where it could in principle be shown to be incorrect. An experiment or test of falsification must be developed that could yield observations that show that the hypothesis is false. For example, we can have a hypothesis that says the leopard is the fastest land animal in the world. To test this hypothesis, we can do a rather simple experiment of calculating the top speeds of fast animals on land. But before we conduct conduct the experiment, we need to make some predictions that state what we expect to see or find if our hypothesis is correct or if we're going to falsify it. It's incorrect. For the hypothesis to be correct, our data would have to show the leopard with the fastest top speed of all land animals. If we find an animal that is faster, then the hypothesis is falsified. It is incorrect. We reject our hypothesis. Next, it's off to conduct our experiments to test our hypothesis. Our data shows that the fastest land animal is the cheetah, not the leopard. The cheetah can reach up to speeds of 80 miles per hour. Therefore, our hypothesis is falsified. When a hypothesis is falsified, we must refine, alter, expand, or just plainly reject the hypothesis. We could alter or expand our hypothesis to be the cheetah is the fastest animal on Earth and then compare the cheetah's speed to top speeds of flying or swimming animals. If we go back to our other hypothesis of all reptiles have two pairs of holes behind their eye orbits. This hypothesis is falsified when biologists look at a sea turtle skeleton. Sea turtles do not have any extra holes in their skull. They actually have zero holes in their skulls. So we falsified our hypothesis. We could alter, expand, and the biologist could come up with another hypothesis to say that all dinosaur reptiles have two pairs of holes behind their eye orbits. However, this could be a challenging hypothesis to test because what if you looked at a hund dinosaur skeletons and found that they all had two pairs of holes? Is that enough skeletons to make this hypothesis correct? If not, then how many skeletons do we need to look at? A thousand? 10,000? Every single dinosaur skeleton? It is easy to falsify a hypothesis. But what about if we did not find any evidence to falsify a hypothesis? If we have a hypothesis that we failed to falsify after the experimenting, the testing, this does not lead to proof that the hypothesis is correct. Nothing in science is provable. New observations or future research may find our hypothesis to be false and they will falsify it. Hypotheses are only tentative accepted and are often assigned a measurement of confidence. For example, our hypothesis of triceratop dinosaurs are only found in North America and based on current research, triceratops have only been found in North America. And there is no evidence to reject this hypothesis based on plate tectonics and where the continents were when Triceratops were alive during the Cretaceous period and the amount of research conducted. Scientists would say that this hypothesis has good to strong confidence in being accurate. But since not all Mesazoic rocks have been studied around the world, this hypothesis could be rejected in the future if a Triceratops skeleton is discovered on another continent. Uncertainty is a part of science. However, some ideas are so overwhelmingly well supported that to reject them at present is unreasonable. These are what we call scientific facts. If a hypothesis is tested repeatedly by many researchers, it can become a scientific theory. A scientific theory must be consistent with most or all available data and with other current theories. A scientific theory is well tested and widely accepted view that the scientific community agrees best explains certain observable facts. It more specifically describes explains and makes falsifiable predictions about related sets of phenomena based on rigorous observation, experimentation and logic. Like hypothesis, scientific theories are not proven as future research might find evidence to falsify them. Most scientific theories are about largecale ongoing phenomenons like germ theory of disease and plate tectonic theory in geology. You may have also heard of scientific laws. The term scientific law in the sciences was largely abandoned in the 20th century. Most scientific laws are scientific theories that are mathematical equations. And just for your easy reference, here are the steps of the scientific method. If you have any questions over the material we have covered in this lecture, please reach out to me.