Hints to Help Produce a Good Lab Write-Up
It is important to understand why you have to “write-up” a lab. A laboratory report is a tool used in science to communicate. Somewhere in the far distant future, a fellow scientist will come across your reports and will wish to duplicate your experiment because you results have some critical impact upon their own experiment. In order to be sure that your original results were indeed accurate and not pulled out of thin air, they must be able to duplicate your procedure exactly. This is where accurate and effective communication comes into play. You must convey the importance of your research, the direction your research is going, the exact methods, the materials, the reagents you used, and the results of your experiment. Finally, you should discuss these results and their significance, or lack thereof. For this purpose, Science has come up with a format for conveying this information. It is called the Scientific Method, and this is how it is written up:
Introduction: This is where you convey the background, the history, the relevance, the “why should we care” about this experiment. For example, if you are doing a lab on determining particle density of a specific soil, you would discuss why particle density is an important thing to know, how does it affect other soil properties?
Object/hypothesis: Here you specifically state, usually in only one or two sentences, what you are attempting to prove, disprove, find out, determine, examine, make sense of, etc. The objective is written as a somewhat general, open ended statement: “The objective of this lab is to determine the particle density of the soil sample.” The hypothesis is a much more specific statement of fact that can be supported or unsupported (you can never “prove” anything in science, only provide evidence to confirm or deny something) by the data you present. For example: “my hypothsis is that this given soil sample has a particle density of 2.65 Mg/m3.”
Materials and Methods: This is the “meat” of the experiment. Here you include the equipment, procedures, reagents, etc. Think of it as the recipe portion. List the ingredients, and the steps to combine them to get the final product. You should also include any equations you use to perform the calculations, and define your variables and unknowns.
Results: So what did you get? Include all the actual measurements you took, work out the calculations here by plugging in your experimentally determined variables. Do Not Discuss Anything Here.
Discussion: Now you can chew over the results and assign some meaning to them. How meaningful are your results? Are they what you expected? If not, why not? What might have influenced the results? What do the results say about the other properties or characteristics? It is also important to discuss any “screw-ups” here. Don’t feel bad if you did something wrong in the lab. There is no “right” or “wrong” science, only “good” and “bad” science. “Good” scientists record everthing they do, whether it was what they were supposed to do or not. That way, the future scientist will know what to look for, or how to avoid making the same mistakes you did, or why their results didn’t come out the same as yours. Just think, if Archimedes hadn’t filled the tub too high, he wouldn’t have discovered the law of displacement!