How To Write A Pre Lab

Some Tips on Writing Lab Reports

Written by Wun Chiou

(A Former UCLA Showtime-Year Lab Courses Didactics Assistant)

A lab report is more than than simply something you plow in to (hopefully) go a good grade. It'south your opportunity to show that you understand what is going on in the experiment, which is really the most important part of doing it. In addition, I retrieve it'southward actually very good practice for getting across your thoughts about the science you lot are doing in a manner that the reader can understand.

What you write in your laboratory notebook is an bodily account of what yous have washed in a given experiment, like a very detailed diary. You should be able to come dorsum to it at some point, read what you wrote before, and reproduce what you did before. So should anyone else reading your notebook, for that matter. That fashion, if you lot make some amazing discovery, like blueish aspirin is better than white aspirin (btw: don't eat anything in, from, or created in lab to see if this is right), you will have a permanent record of information technology to remind you of your greatness. In that location are three basic parts to a lab written report: pre-lab, in-lab, and mail-lab. In this document, I've written some helpful tips that might help you through your lab-written report woes. I won't include everything you take to do (you should look on VOH for the report guidelines), merely only a few key ideas.

PRE-LAB REPORT

I. Introduction

The introduction discusses the problem beingness studied and the relevant theory. Ideally, it would take up about 4-five sentences. The main thought here is to give the reader an thought of what you lot are going to do in a short paragraph. There are different styles to practise this. You should try to write it in your own words, rather than paraphrasing or quoting the lab manual (but if you take to, exist sure to include the appropriate references). It'southward always a good idea to read the entire experiment in the manual earlier you lot begin your introduction. I suggest the post-obit:

Background sentences: state why yous desire to do the experiment, why is it relevant, what other kinds of similar experiments accept been washed in the past.

Goal: In one sentence, land what y'all are going to do in the experiment and what you lot promise to discover. This is probably the most important function of the introduction. You should as well list explicitly any main chemicals with which you are dealing (vinegar, aspirin, NaOH) and whatsoever techniques you will be utilizing (titration, recrystallization, spectrophotometry, etc.). For example, "In this experiment, we will determine the buffer chapters of a weak acid buffer of acetic acid / acetate ion by titration with both a stiff acid, HCl, and a strong base, NaOH."

Other procedures or theory: If you need to elaborate on some of the techniques you stated in your goal (or couldn't state in your goal), you tin write a couple more sentences about them afterwards. Or you lot tin can add anything else that you might call back is relevant, similar additional major procedural steps you will take.

Go along information technology sho rt!

Ii. Procedural Flowchart

This part of the pre-lab should take no more than one page. A good flowchart should give a reader an immediate idea of what's demand to be washed in the laboratory except in a less detailed format. Think of a flowchart every bit a "road map" of the experiment. Information technology gives a reader a "pictorial" representation of the experimental procedure. In general there are ii major steps when constructing the flowchart. First, read the experimental procedure carefully. Second, rewrite the procedures in a flowchart format. Continue in mind that the flowchart should be brief and comprehend all the steps in a simple and like shooting fish in a barrel to follow manner. In that location should be no complicated sentences or paragraphs in the flowchart. Yous will have to practice a lot of rewriting in order to simplify the procedures into a flowchart format. This is exactly why nosotros desire y'all to do it. This gives yous a adventure to Remember near what you read and how to rewrite information technology in a way that can be implemented into a flowchart.

Ever remember to reference where the experimental procedures are coming from in the pre-lab written report.

Please DO Not only copy the unabridged procedure (or majority of the procedure) and brand it looks similar a flowchart.

IN-LAB RESPONSIBILITY

I. Information-taking

Always write in pen. You can't really erase anything, anyhow, because of the carbon paper below it. White-out is a big no-no, as well.
Always tape information directly into your lab notebook. I know some people like to be neat, and have nice formatting and all that, but information technology's more important to make sure you lot record all of the information immediately in case you lot forget what you wanted to say later on or you forget to copy other information into your notebook.
Never scratch something out completely. Yeah, nobody's perfect and of grade likewise nobody wants to be reminded of that, but you may observe that yous were right in the get-go place, and now you wish you could read what you wrote before. Also, if yous make a mistake information technology'southward a good idea to go along a record if information technology and so y'all (or someone else trying to practice your experiment) can call up to not brand the same mistake twice.

Two. Observations

In improver to writing downwards all those numbers (information), yous should keep an eye (nose, ear, etc.) on what is really happening in the experiment. If yous add one thing to another and it evolves a gas, gets hot or cold, changes colour or odor, precipitates a solid, reacts really apace or slowly, or anything noticeable, you should write downwardly that observation in your lab notebook. Other things to consider including are: brand and type of any motorcar y'all are using, concentrations of all the standards y'all used, and etc. One of the reasons y'all are doing this goes back to what I said most mistakes earlier. An experiment is exactly that: an experiment. If information technology turns out that you get an unexpected result, you can go back and trace your observations to see where the mistake occurred. If you don't accept any observat ions, this is really hard to do. The bottom line: write what you practise and do what y'all write.

POST-LAB REPORT

I. Information once again?

Recopy your data from the in-lab hither in a nice peachy format (tables are ordinarily nice and neat). This is your take a chance to organize it into a more readable course now that you are done with the experiment and impress the TA with your organizational skills.

Ii. Calculations

It's a good thought to write out all the formulas you utilize in your calculations. Personally, I like to work through the trouble using just the formula, and then plug in the numbers at the finish to get my concluding answer. Too, show all of your work.
One more point is to be sure to include the units when yous are doing a calculation, and don't drop the units halfway through the calculation. This is really a pretty powerful tool because if your answer has the incorrect units you know you lot must take made an error somewhere along the fashion. Conversely, if your answer has the correct units, yous could notwithstanding exist incorrect, only at least you lot are on the right track (and probably much of the time your reply is correct, besides!) You can fifty-fifty exercise the calculation using just units and no numbers and come across if the units cancel out in the right mode to test if you method is adept (this is called dimensional assay).

Three. Conclusion

The determination is alot like the introduction except, instead of a summary of what you are going to practise, it's a summary of what y'all did. The reason you take a conclusion is because your lab written report might be long and the reader may not retrieve all the of import points that y'all stated. Also, it gives you a chance to explain anything that might have gone wrong or could be improved, besides as propose future experiments. Like the introduction, it should be brusque and to the point. Again, these are only my suggestions, but here's what I think you should e'er include:

What you lot did: Reiterate your procedures briefly (including whatever changes you lot made).

What yous found: Restate any results that you may take calculated (with errors if applicable). You don't need to include the raw information, but if you calculated an average over several trials, state the average (non each trial). Usually you lot want to study the results as x +/- y (like 2.345 +/- 0.003), where y is the absolute error in x. Another choice, if you lot calculated the relative error, is x +/- z% (like 2.345 +/- 0.five%), where z is the relative error.

What you lot think: What exercise your results mean? Are they good? Bad? Why or why not? Basically, annotate on the results. If your experimental error (RAD, RSD) is small or large compared to the inherent mistake (the error in the standards and equipment used), comment on what this means, besides.

Errors: Speculate on possible sources of fault.

Source: https://www.chem.ucla.edu/~gchemlab/labnotebook_web.htm