hello AP biology students I'm going to start a new series here where I go over the different units in the AP Biology class specifically this first one's going to be about unit zero this is going to be the precontent or the kind of math and statistics and science that you're going to see and want to know about before you get into the actual content of the class in this unit I'm going to organize it into seven different sections you can see them here and each Tik Tok is going to kind of review the content of each section so without further Ado let's get into it section 0.1 is basically going to just be a review of Science in general specifically the scientific method and how we do science something that I like to reiterate to my students is that science is a verb it's not a thing it's not just memorizing a bunch of facts it's a process of gaining new information about the observable universe now within science we have these things called hypotheses and in biology and science we usually just say that a hypothesis is an educated guess but something that's really important about a hypothesis is that it's capable of being tested Ed and possibly falsified by evidence this just basically means that we have to be able to physically or scientifically test this hypothesis and this hypothesis has to be able to be falsified which means disproved and typically these hypotheses need to be consistent with the knowledge that we've already gained through experimentation a great example of a hypothesis is the bell will ring at the end of the period that might sound like a fact but it's still a hypothesis since it's a prediction and we can test test that hypothesis we can use observations to test it and we can take data from this experiment now in upper level AP classes we actually will have two different types of hypotheses and I'm going to get into more about these hypotheses later on but basically there's the null and the altern of hypothesis the null hypothesis is stated there is no significant difference between the expected and observed data I know this may sound confusing but the null hypothesis basically allow scientists to test the validity of an experiment null hypo IIs testing allows scientists to really analyze if two variables are going to be influencing each other or not the other type of hypothesis is called the alternative hypothesis and this is typically just like your regular hypothesis this is what the researcher is basically trying to test during this section I also like to go over just general terms that we use in Biology one of which is being a fact a fact is an observation that can be repeatedly confirmed and an example of this is water freezes at 32° F we can observe this and go back and observe this time and time again and see that water freezes at this temperature now these observations don't always have to be taken by our site you can use instruments you can use scientific devices you can use other senses but basically these are just observations that can be repeated a belief is a claim that's not supported by disproval evidence and there are other definitions for belief but I like this one the best an example of belief is aliens exist and this is a belief that I have we don't have any scientifically disprovable evidence that supports that aliens exist and this is a belief that I have but it's still a belief it's not a fact because we can't go back and repeatedly confirm that aliens exist now this belief may change as we gain new evidence but until that time it's still a belief pseudo science is a collection of beliefs or practices mistakenly regarded as being based on a on the scientific method astrology is the thought that the positions of the planets affect human behavior basically and there is no scientific disprovable evidence that supports this there's actually a lot of evidence out there that disproves this astrology seems like it is scientific because they take observations but they're not disprovable observations next we have something called a theory a theory is an explanation of how or why certain phenomena occur in the natural world theories are based on extensive observation experimentation and something called the peerreview process something that's really important for people to understand is that theories can and often do change and that goes against what people kind of perceive science as I think the perception of science from society is that science is unchanging and that's not the case theories often do change they become more accurate they even change how they understand or explain certain Concepts but it doesn't mean that science is wrong A lot of times our scientific method leads us to become more accurate with our understanding of certain processes something else that I think is really important for people to understand about theories is that they are falsifiable which means they can be disproven I'm going to go into a deeper understanding of what a theory is using different analogies in a little bit a scientific law on the other hand describes what's happening and these are usually mathematical in nature and under certain circumstances for example F equal ma Force equals mass time acceleration that is a law because it's describing what happens it's not describing how or why that's happening it's just just describing what is happening it's again important to understand that a scientific law and a scientific theory are two separate things and one is not better than the other they just explain science in a different way here's a simple way that a student actually showed me that I absolutely love about remembering the difference between a theory and a law remember that the word theory has an h and a y in it and the word law has the letter W that's because theories explain how and why things happen while laws describe what happens if you don't take anything from this one section I would take this theories do not become laws with more evidence I think there's a again misunderstanding from society that we start out with hypotheses we move to theories and then we become a law when it's not the case theories and laws are two separate things a theory will never become a law with more evidence because they describe two different sets of ideas for example evolution is a theory because there is a huge amount of indisputable evidence for its occurrence Evolution has been tested time and time again and all of the scientific evidence supports that Evolution occurs however Evolution will never become a law because they're just describing two different things something else that I'd like to point out at this point is that science doesn't prove anything in my classes I actually kind of joke around and say that the prove or the p word is a swear word in my class because again science never proves anything I love this quote from Albert Einstein no amount of experimentation can ever prove me right a single experiment can prove me wrong science tends to disprove ideas in order to come to a conclusion that is supported by the evidence but again you can never prove anything in science because what amount of evidence does prove something in science proofs in math or proving things in court are very different than how science goes about discovering things all right so here's an analogy for what a scientific theory is imagine there is a shape behind this White Blank Space and you can feel around the shape but you can't actually see what the shape is with your own eyes so what you start doing is you start feeling around these different locations and start taking data points so you get some data and you start hypothesizing and making conclusions based on this evidence so obviously it can be a triangle it can be a diamond it can be a circle it can be a square but it can't be a line the evidence does not support that it's one straight line so like in science we experiment more and find more data we feel around the different points here and we find these points and we conclude from the evidence that the evidence supports that this is no longer a square or a triangle it could be a circle it could be an octagon it could be there could be a lot of lines in between here that makes it look like a sun but we know that this shape is no longer a square the evidence does not support that the shape is a square because it just won't make sense so again we experiment more and find more evidence we disproved that it's an octagon now it's starting to look like a circle but we can't for sure say it's a circle this is what I mean by saying we can't prove this is a circle we can't look behind the curtain here and see that's a circle however all of the evidence does support that it's a circle and the evidence disproves that it's a square so again we find more evidence and again it looks like a circle or a badly drawn Circle but a circle but we can't for sure say that we proved this Circle all of the evidence supports that it's a circle but we can also say that it disproves that it's a square by taking account of all the evidence and data and observations that we've taken about this shape we can confidently say that it's a circle but we can't prove this circle we can say that all the evidence supports this circle but again this is what a scientific theory is you can never prove anything to be true in science but you can say that all of the evidence support that it is a circle