hi it's mr. Andersen and in this video I'm going to talk about the nature of science this really is the first video I ever should have made it's about science what it is big picture and the best way to describe it is it's a way of knowing now there are other ways of knowing like religion and philosophy what sets science apart it's a specific way of knowing and understanding the natural world it assumes a certain amount of order and consistency in the natural world but assuming that scientists just followed their curiosity they develop investigations make observations gather evidence once they've done that they weave those observations into an explanation first hypotheses and then theories but they know all along that this knowledge is tentative that it'll change over time our understanding of the natural world will get better and better because of this feedback loop we're constantly critiquing the evidence we have and the investigations that we make now there's a real simple model of what science is and I've left out the best part it's a human endeavor it's done by humans we bring with us our lack of objectivity and the experiences of a lifetime but it's a very exciting career and I would encourage you to if you don't go into it at least understand how it works so science is a way of knowing but it's not just the knowledge itself it's a way of observing the natural world and coming to a better understanding it's built on skepticism and evidence and explanations but over time we understand our natural world in a better way and that's all we can understand in science the natural world what we can see and what we can gather observations on as far away as a distant galaxy or a zoomed-in as the hydrogen wavefunction there are certain questions that we can't answer what lies outside of the natural world the supernatural world so we can't answer the question does God exist it lies outside of science and we also can't answer questions related to ethics and values now we can contribute evidence to those questions but we don't know what the right answer is in science it's a human question and as we look at the natural world and zoom out from the earth out to the solar system then we go to the galaxies and farther away into these massive super clusters in the observable universe there's an assumption in science that the laws that rule are natural world here apply throughout the universe and they have done so through time now what lies outside of that we don't know are there multiverses a lot of that we don't know and so that lies outside of science but looking at that natural world we develop a better understanding through investigations individual scientists not following some kind of a scientific method but following their curiosity trying to answer the questions that they have now it's tied hand-in-hand with technology some of it is hypothesis driven a lot of it is simply just discovery but once you discover something new once you explain how the world works then you make a poster and you go to a poster symposium and share it with a lot of other scientists and they'll look at your poster you'll look at theirs you'll work together on other posters and eventually you might publish in a research journal like nature or science now other scientists can look at that and they can replicate your results now a lot of the science is now becoming available online so you can see these open access peer-reviewed journal articles like +1 I would encourage you to go there and look at the science that's being done right now and as you look through those articles some will be confusing but they'll be filled with evidence because that's what we do in science we make observations and collect evidence qualitative quantitative so an example Einstein 100 years ago proposed this idea of gravitational ways that if you have two massive objects like black holes run into each other it'll send these gravitational waves through the universe so scientists have to observe that we have to collect evidence we built a massive LIGO a laser interferometer gravitational-wave Observatory and what we're looking as we bounce lasers back and forth in this massive structure are these gravitational waves and we finally heard them in 2016 twice we've had these ripples moved through from these massive black hole collisions and we replicate the data we've gotten one in Washington state in Louisiana so we make sure that these are not anomalies but once we have evidence then we can build a better theory a better understanding of the natural world so these observations are the what we're seeing but they're not the why or the explanations if we put that on the matrix if we're looking at one single event if we observe something that's a fact so if in an Apple falls that's a fact if we see change in the gene pool over time that evolution is a fact if we can apply it to all events then it becomes a law and generally a law is going to have a mathematical formula associated with it like the gas laws are a good example of that but it's not explaining why this is occurring as we do that we move into the area of a hypothesis so a hypothesis isn't just a guess it's a scientist coming up with an explanation for a set of observations it should be testable it has to be falsifiable but once we test that then we can build those hypotheses over and over and over again into something that explains all events called a theory so we could say evolution change in a gene pool is a fact natural selection is a theory that explains the mechanism or the why behind behind how that is occurring so let me give you an example if an apple falls that's a fact Newton notice this and notice a lot of other things planets moving around each other and generalize that to Newton's universal law of gravitation it's got a formula that goes along with it where we can look at the force between two objects as the mass divided by the distance between them and times the gravitational constant but that's not explaining why so scientists we're looking on that as well is it maybe something to do with the nature of an apple that it wants to be on the surface of the year that's really hard to falsify that but early scientists were thinking that way but maybe it's something in the air or maybe there's some a genera force or it's like a magnet or maybe it's the curvature of space-time these are all different hypotheses we have to test them there have to be observations and experiments that are set up to figure out which of these hypotheses is correct and Einstein came up with the idea that we generally use today it's general relativity but as we zoom into the very small it falls apart so we continue to look for new theories so this whole idea of theories changing really resonates this idea that science is constantly open to revision and change so an example could be disease we used to believe in this miasma theory of disease spread there was something in the air or bad air so this is a depiction of a cholera outbreak a malaria Moll air means like bad air and so scientists started to test this and so John Snow who was a doctor started looking at a cholera outbreak in London and found that all of the diseases were in a very similar area and they were all using the same well so we could track it down to that one point not in the air but in the water and then scientists like pass through or were able to develop a pasture flask where we could allow air in the flask but not the bacteria and it was a way of ruling out the miasma theory in favor of the germ theory now this process continues today but science is a human endeavor as we look at this Jennifer Doudna she's a researcher at Berkeley who helped who's helping us decode this idea of CRISPR and how we can edit DNA with it and as you look at her research article it seems to be just knowledge that's set but it's constantly changing this is her lab their Twitter account and science is done by people like us people like you and the best way to understand it is to get into the lab and understand what's going on I would highly suggest watching this science vlog this is Alex Danis she's getting her genetics PhD at Stanford and she's showing what it's like to be a scientist and to do science and so in review what do we study in science the natural world how do we do that through investigations to gather evidence we then make sense of those to build explanations but there's this process of critiquing so that we constantly are improving our knowledge of science so that's the nature of science and I hope that was helpful