How to Write a Formal Lab Report

all right ladies and gentlemen in this video I am going to be talking to you about what is necessary how to write a formal lab report what are the different sections and what needs to be in each of these sections this way you can refer back to this video throughout the year quick comment before we get started you can be writing about two of these per quarter and remember I do grade these on a on a sliding scale essentially where you are I assume that you have not written one before and I want to teach you how to write one so know that for the first half of the year your grade is going to be helped out when you’re writing these formal lab reports but in the second half of the year by then I’m hoping that you would have learned what I’m looking for and you won’t get any bump in the grade so there the first thing to talk about with these formal lab reports is that there need to be five distinct labeled sections so I should see when I look at the front page of your lab report your name the title of the lab and then underneath that introduction actually labeled so I don’t want this in one big long paragraph format it needs to have distinct sections so there’s the introduction section there’s the materials and methods sections and we do want to use that phrase there’s the results section there’s the analysis section and then there’s the conclusion section five distinct sections each one is labeled these different sections serve different purposes in the lab report which is what I’m going to be talking about in this video so first up is the introduction what does it do what is the point of the introduction the point of the introduction is to give all necessary background information to whoever happens to be reading your lab report to make sure that they understand the language that you’re going to be using so key definitions if we’re doing a lab that has to do with molar mass then you would need to define what molar mass is in the introduction that way when the reader gets to the section where you’re talking about calculating molar mass they know what it is that you’re calculating so all necessary background information that is the point of the introduction how is how do you structure the introduction basically what needs to go into it with a little more detail than just background info well first off you want to start with the purpose of the lab you always want to start with this this purpose statement you know in this lab we will be doing fill in the blank then after you introduce the purpose of the lab that’s when you want to cogently and coherently go through the background information so you want to think about what order you’re giving this information in that you’re not just listing it off like a series of definitions that’s not what it is this is paragraph format you are having a dialogue with the reader so you really need to think about what order you think you should introduce the material at the end of the introduction once you have gone through and talked about all necessary background information now you want to start relating that background information to what you’ll be doing in that lab so you’ll say well today we’re going to be determining graham formula mass and in order to do that we will be taking the following measurements that will allow us to then calculate the graham formula mass so you’re relating the background information to your task at hand what tends to use tenses change throughout the lab reports I the introduction will always have a future tense meaning you have not yet done the lab you are preparing the reader to do the lab so the lab is going to take place in the future so notice all the stuff that I was talking about with introduction we will be finding graham formula mask we will be taking the following measurements you’re using future tense the next section is the materials and methods section this is essentially your procedure but it’s not just your procedure from what you wrote in the lab note but this is essentially the part of the lab report where you’re saying what you did so what is what does it do is a point of materials and methods it gives your reader enough information so that they can repeat the lab that’s the idea if they wanted to verify your results they can look at your materials and methods section follow your instructions and they can repeat what you did and hopefully get the exact same results because after all in science things have to be repeatable how do you structure the materials in methods section first of all I want you to use paragraph format I do not want a series of numbered steps here real scientists writing real journal articles do not use numbered steps in the materials and methods section you are real scientists in this class you’re going to write like real scientists I want you to have enough information so that the lab can be repeated precisely meaning you have gotten in the original handout mass out between 10 and 20 grams of something but on the day of the lab you have a very specific number that you ended up passing out I should see that specific number and not that between 10 and 20 grams so it has to be exactly what you did on the day of the lab if there are any changes from when you originally thought of your procedure for the pre lab notebook they have to reflect it here so it really needs to be what did you do on the day of the lab what tends to use you’re using present tense and you’re using objective language you’re using objective phrases meeting way evaporating dish obtained beaker place on hot plate you know you’ve written a good materials and methods section if you notice that a lot of your sentences start with verbs and tend to be commands because you are you’re telling the person what to do so this is present tense you this is where you’re actually doing the lab next up in the lab report is the results section and I do actually need to talk about this section you know a little bit more because students are sometimes oddly enough confused about what goes in this section this is the part of your lab report where you have all your numbers and all your calculated results not where you explain what your results mean or how you calculated those numbers so what does the results section do basically if there’s a person reading your lab report and they just kind of want to see just you know what numbers you got this would be the section that they turn to so they’re not interested necessarily in what the results mean just what numbers did you get so it’ll for the first lab report of the year it will have things like you know percent composition of nacl and you’ll have your number and present composition sio2 and you’ll have your number so it’s really just your your your calculated results no work needs to be shown here I do not want to see the explanations of how you got those results here that is not what this section is this section is really just what are your data it should also include your data table from the lab so it needs to have both things data table so what numbers did you write down on the day of the lab and then results but you know what did you do with those numbers what what information get you glean from that in from that collected data I do not want to see work I want to say that against it really bears repeating this is not where you show me how you calculate a real results that’s in the next section it really is just numbers it’s like you’re pooping your numbers on the page and then just leaving them there for everyone to goggle at you’re not explaining anything what tends to use well probably you’re not going to be doing a lot of writing in this section you could for most labs you could even have your entire results section in just charge just insert a chart and have labels for each of the things but if you are doing any writing then you would want to use past tense because at this point you have completed the lab and now you’re reporting on it the next section is the analysis section and this is a really big one so what is what does the analysis section do what is the point of the analysis section first of all it interprets all of the data from the lab so here’s that interpretation part that the results section isn’t then it explains all of your calculations all of our calculations are explains explained you analyze your results for possible sources of error you compare your results to other scientists other students in the class and you comment on like how your results compared to their results you think about what could be done in the future to make this slab more effective and yeah if that sounds like a lot it is this is easily the longest section of your lab report and if it isn’t the longest section of your lab report then you’re not writing lab reports correctly and knows i’m not saying my lab reports this is i modeled this format for writing lab reports based on how actual scientific journal articles are presented so you are writing in a format that in science is widely accepted with these different sections what temps are you going to use in this section you’re going to use the past tense you have finished your lab you are commenting on it now so with the lab report you are almost moving through the lab process and the introduction you’re going to do the lab in the materials and methods section you are doing the lab and then results and analysis you have done the lab and you’re looking at your data and what happened so we’re going to go step by step through the analysis first of all you do want to use paragraph format in your analysis section it needs to open with an explanation of your results how you arrived at your results how did you calculate your results so this is where you’re going to put your calculations there are two things that I’m always going to be yelling at you about your calculations and not just well in AP chemistry in general and then specifically for the lab reports number one I want to see all work so i want to see numerical setups I want to see units I want to see original formulas you know what formula are you basing this off of into after you’ve shown me the calculated the calculations you need to explain the calculations why are you doing what you’re doing like how did you know to put that number there even if it’s just explaining well we know that mass goes on top and moles go on the bottom so therefore i put the mass well you’re not going to use i but we put the mass which was 12 grams over the moles which was point 5 and calculate the results be 24 um if there is any graph or chart that we need for the lab you would also want to put to talk about it at the beginning of your analysis section maybe after your calculations or before our calculations it will depend on what the graph or chart was used for and when you include a graph or chart um uh in your lab report and you’re explaining it there too always two things to bear in mind you have to explain first of all how you made the graph meaning how did you obtain the data that went into the to this graph what went on the x-axis what went on the y axis and y and then once you’ve explained how you made the graph how did you interpret the graph what information could you pull from it and why why are you looking at that specific point on the graph what is so special about that specific point on the graph you know why are you looking there so you’re explaining you’re not only how you made the graph but how you interpreted the graph both of those things have to be there continuing on after you’ve talked about your calculations and your results and any graphic trucks you might have made now you’re going to move on to talking about sources of error and every time we write a lab report we’ve got to have at least two sources of error now big big big comments about these sources of error you are not simply listing two possible sources of error you have to really really think about how the source of error impacted your calculated results meaning if you have you have to sort of carry the source of error through your calculations if you spilled your solution that contains salt water that would be a source of error but you can’t just say we spilled the solution that’s a source very you have to say that means that we lost some of the mass of the salt you are not done though because your calculated result was percent composition that was like that was where you were going so you then have to apply that loss of mass to not just the result four percent composition of the salt but how would that impact any other percent compositions would it and explain why in terms of the formulas and the calculations on I give another example here about like PV equals NRT if you’re claiming that a source of error was that your temperature was too high you can’t just say that that was the source of error in PV equals NRT having a temperature too high would have what impact on a calculated mole results think about what having a to large number 40 would you do a calculated value for n then how would that impact gram formula mass if you were using that mole number to calculate grant from the 1s so you’re you really are thinking about how that source of error had an impact on your calculated result to give you an idea for what level of explanation I’m looking for here sources of error when you talk about it it should either be one very long paragraph or two normal paragraphs meaning if you write just write two sentences saying our source of error with it was this a second source of error was this you’re not doing what you need to do you need to thoroughly thoroughly explain how that error impacted the experiment every single step follow it through continuing on with analysis after we talk about sources of error now you’re going to compare your results to others so yes you have to go and talk to other people in AP chemistry and for know what they got and compare it to yours because guess what I get I bet you didn’t get the same result but you all did the same lab so talk to them about what they did talk to them about their results um and share that information here I want to see names of other students I want to see the results of other students and then I want to see you commenting on any differences between your results and their results that’s what I mean when I say compared to others because that’s what scientists do so I just don’t work in a bubble they talk to other scientists who are working on the same thing and they compared to one another you need to reference those other students though with respect so you’re going to use their last names in the lab report you’re not going to use their first names always just last names why do you think there was all so different than yours comment on it and then finally in the analysis you want to talk about future improvements if you were to do this lab again what would you do differently and why that’s a big thing why would you do that differently if you were to give advice to future ap chemistry students about doing this lab what would you tell them what is what are your recommendations up on repeating this lab think reflect on the lab what could be done to improve the experiment that’s the analysis section is easily the longest section of the lab report and that will take you hundred percent the most time I guarantee it and then lastly is the conclusion ironically we just finished the longest section in the lab report and now we’re going to have the shortest section of your lab report the conclusion is as brief and to the point is possible the conclusion is not a time for explanation the conclusion is simply a time for summing everything up that is the point of the conclusion you simply straightforward and to the point say what you did and your major results and really that’s about it that that is it you do not go into any level of explanation here essentially the idea is you notice you are going to be repeating yourself throughout the lab in the introduction you’re saying what it is you’re going to be doing in the materials methods section you’re describing how you what you did on in the results section sorry in the analysis section you’re explaining what you did and why it worked out the way it was and then the conclusion you’re saying it again yes you are going to be repeating yourself over and over again the point is that scientists tend not to pay attention to things so we have to have things shouted at us several times so we’re hoping that by the time the reader gets to the conclusion they’ve actually figured out oh they separated a mixture and found percent composition that was unclear up until this point in time how do we structure your conclusion you really only need three things in your conclusion you want to open with the statement about what you did in the lab one or two sentences max this is not a procedure it is just so what did we do in this lab um then you want to state your major results so the big results not like you know what’s the difference what was the difference in mass between the beaker with the stuff in it and the beaker on its own no no major results so percent composition um then after you’ve stated your major results then you want to talk about sources of error not explain them though just restate them just say what they were so this is your like two sentences on sources of error this is very very very short section like I said you could do three sentences and as long as you hit those three points what you did what you got and what went wrong that’s basically it you’re done with your conclusion what tons of your using your using past tense you have finished doing the lab and you’re summing everything opps you’re using the past tense in this section and one final one final comment on this is a formal document this is very formal document use formal language we don’t I don’t like to seek attractions don’t like to see contractions don’t like to see abbreviations those are all in formalities and this is a very very formal document so to that end you always want to use last names rather than first names when you’re talking about other scientists use their last names other students use their last names don’t use first names and along the same lines no plural pronouns no I you I’m sorry you only want to use plural pronouns you do not want to use personal pronouns do not use I do not use me do not use mind do not use you you want to always use wii u want to use our you want to use they I take cough points every single time I see something in your lab report that says I then determined the grand formula mass to be no no no use we all the time scientists do not work in isolation so even if there’s just on the rare occasion that there’s just one author on a scientific research paper which is very rare in this day and age usually there’s a minimum of five scientists attached to a scientific journal article um even it’s just one scientist they will still be using we in in their writing so you do not use I me aur mai anh searched document before you turn it in is so easy to do just search it for I me my you mine stuff like that and lastly do not wait to the last minute to start this is a multiple page assignment this is a big assignment this is not something that you can do the night before and if you do it the night before you’re doing a very very poor job I don’t have a minimum length so I’m not telling you that each lab report has to be a certain length because it will vary from lab report to lab report it depends on what we did in the experiments some labs require on different types of explanations some labs have data that takes up a large amount of space so I don’t tell you there has to be a minimum amount but if your lab reports two pages long I am lining up my red pens because I know I know based on what I’m looking for that there’s no way you give me everything i’m looking forward to pages i’d say if you want to shoot for a pretty decent lab report to know what level of explanation you need i’d say you want to shoot for more like three to four and the really great ones they’re more like five plus just to give you an idea but it varies from lab to lab it really really does vary from lab to lab and student student so that’s what i have to say about lab reports refer to this throughout the year and whenever I ask you to write a formal lab report this is the type of document I’m talking about and i’m going to give you an example of this in class I basically wrote a fake lab report that shows you the level of detail I’m looking for in these in these sections