Instructions for Writing Lab Reports
Peer-reviewed scientific papers are usually structured in a way that is different from the papers you are used to writing. You will need to use the correct structure and formatting to maximize your score on lab reports.
All lab reports should be sequential, meaning that the oldest labs should be on top and the lab you just completed should be at the back. Data that you collect during a lab period should be handwritten and appear at the back of your lab notebook, which should be kept in the lab at all times. When you are finished writing up your lab report, punch holes in it and place it in your lab folder at the back of the room.
A few formatting guidelines apply:
• Times New Roman 12 pt. font
• One-inch margins on all sides
• Paper should be double spaced except for tables, table captions and figure captions.
• Pictures and graphs are all considered figures. Figure captions appear underneath.
• Table captions appear above the table.
• Equations that are referenced in the text should have equation numbers.
Header
Each lab should be numbered sequentially, with the title that appears in the syllabus. The date and time that the lab was conducted should appear in the right hand corner. The lab title should be in bold lettering. In many scientific papers, an abstract appears under the title, but these labs are so short that an abstract is unnecessary.
Experimental Methods
Begin this section with a general statement explaining what you are trying to measure or understand. Think of this section as something similar to a cookbook: you are giving step-by-step instructions for how to set up and run the experiment. The only difference is that it must be in paragraph form and use the passive voice. This means that you must avoid words such as I, you, we, my, our, etc. Another common mistake is when people issue commands ("hold the mass hanger still," or "wait until 30 oscillations have occurred.") These sentences can be restructured as follows: "The mass hanger was steadied before release to minimize horizontal movement," or "The stopwatch was in operation for a minimum of 30 oscillations."
When using sensors or other laboratory equipment, it is important to mention the brand name and model as well as the precision and settings used for the experiment. I will remind you to do this during the lab. You will need to measure the mass and dimensions of some of the items used in lab experiments, as well as to make general observations of the experiment itself. You do not present graphs, perform data analysis or discuss results in this section.
You will usually need to include a picture of the lab setup in the Experimental Methods section. I will provide this to you via Google Drive, which you can then import into a Word Document. The picture should take up no more than half the page and it should have a figure caption underneath.
Results
In this section, you are pointing the reader to where the data and graphs are located. Begin this section with something like: "The horizontal distance of the projectile launcher as a function of angle can be found in Table 1." Tables should appear within the results section, somewhere after the first paragraph. You want to avoid having tables run across two pages, so bear this in mind when you are constructing your table.
Tables should have an outside border, vertical divisions between columns and a horizontal division underneath the header. No horizontal lines should appear within the table itself (see Table 1 below). Column widths should be reduced to eliminate any extra space and a table caption should be placed above the table using single spacing. It is recommended to use abbreviations in the header, where they are explained in the table caption. Headers should be bold and centered.
In many situations, there will be a linear relationship between the independent and dependent variables. You should use statements such as "The acceleration of the hanging mass was plotted as a function of mass difference, as shown in Figure 2. The data were fit using a least-squares linear regression, yielding a slope of X.XX m/kg/s2." Keep in mind that your first graph caption will be labeled Figure 2, since it comes after the picture of your experimental setup. See the Excel tab for tips on how to format graphs.
In some lab reports, you will have derivations, which will appear in the results section. Some derivations also require schematic diagrams, which should also have figure captions. If you omit any data points because they are in error, they should be discussed in this section. You should not discuss the meaning of your results or compare them in this section.
Discussion
In the last section, you discuss any trends or patterns that appear in the data. For instance, is there a linear, parabolic or hyperbolic relationship between variables? How well does the experiment follow theory? What are the sources of error in the experiment? What are the limitations of the sensors used to collect data? If you had difficulties obtaining reliable data, how might the experiment be improved? What physical principles were demonstrated in the experiment?
One common mistake that many students make is to focus more on sources of error than on the meaning of the results. This might manifest itself in a statement such as "There was a lot of error in this experiment." For many of the experiments performed in this class, you should be achieving a percent error of less than a few percent, which is considered to be decent. In other labs where friction is minimal, you might do even better. A more worthwhile pursuit is to compare your errors with other groups to see if there is a systematic error or to see if one group is an outlier.
Another common mistake is to simply list all the errors that you can think of, without bothering to consider that some of them might be negligible or unimportant. You are welcome to discuss these issues with me as well as your interpretation of your results at any time. Many students give me a rough draft of their report a couple days before the deadline so that I can offer suggestions.