Guidelines for Writing a Lab Report

Appendix A Lab Reports Basic Rules and Guidelines for Writing a Lab Report Preparatory Comments It is important that every student get the opportunity to write concise laboratory reports about his or her experiences with the exercises in this manual. This will not only give the student writing practice, but will also help students to organize and evaluate their results in terms of the scientific literature. The format of scientific writing is more restricted than a short story or novel. Scientists, when reporting their research results to a journal, are not given wide latitude with respect to style, but must follow carefully conscripted conventions. Each portion of a journal article (abstract, introduction, materials and methods, results, discussion, literature cited) has a particular limited purpose. All of the parts integrate into a meaningful whole that precisely reports the results and importance of that research study. It is, therefore, the contention of the authors that a well-written laboratory report should emulate the format of a scientific journal article. This approach is particularly germane to those students who intend to enter into careers in research or other areas where the written expression of ideas is of vital importance. Finally, it is advised that each student read numerous journal articles before he or she attempts to write a report based on that format. The Portions of the Report A note before you begin: Certain practices are appropriate for a college-level assignment and certain practices are not appropriate. For example, it is expected that reports will either be typed (or word-processed) or carefully printed, but not written in longhand. Also, the use of lined notebook paper is not appropriate for a laboratory report as it indicates a “work in progress” and not the finished product. Completed reports should be stapled or held in a binder and not handed in “loose” or paper-clipped together. Of course, poor syntax, atrocious spelling, etc. are not acceptable practices for any college-level writing assignments. Title Page (2) This is the cover page. Devote an entire page to the following in this order: Name - (section number) Title Date Performed: Date Due: Lab Partners: TA for the experiment: Abstract Not required for this course. Introduction (10 points) The introduction is one of the most difficult portions of a laboratory report to write. There is no specific length for this segment, although extreme length and wordiness are to be avoided. For most topics, a page and a half should be sufficient. The primary goal of the introduction is to summarize the scientific literature only with respect to the main topic of the laboratory exercise. It is difficult to determine how much information should be used, although very general data that would be known to a biologically literate reader should not be included. For example, if the exercise concerns the use of a specific histochemical stain and its effect on isolated rat neurons, it would not be appropriate to include in the introduction a lengthy history of light microscopy or a detailed explanation of the structure of a rat’s brain. The introduction should instead summarize prior experimentation (if any) in the area that was explored in the laboratory exercise. Consider physiology journals, the textbook, class notes, and this laboratory manual as literature resources. A good report, however, should go beyond the text and the laboratory introduction and delve into additional literature. An introduction that merely summarizes the laboratory manual is not acceptable work. Finally, the last paragraph of the introduction should always be a statement of research goals for the forthcoming laboratory exercise. The expected importance and hypotheses of the project should also be briefly addressed. Materials and Methods (4 points) This section should be written as a complete paragraph and include a concise list of all materials utilized in the experiment. Also, a very brief, general description of the experimental procedure should be included (e.g. dissections, initial instrument settings, etc.). This section should be written in first person, you are performing the experiment, tell me what you did. Moreover, It should not be an instruction manual, do not tell me how to do it, tell me how you performed it with enough detail so that I could do it myself. More detailed explanations of specific experimental manipulations should be included in the results section. Results (12 points) The results section of the report should include an exposition of all the data expressed (if possible) numerically and organized into figures, graphs and tables. For a number of the exercises, you will be presenting not only data that your group has collected, but the tabulated data collected by all of the groups in all sections. The reader should be directed to important features of the results with appropriate narrative descriptions including detailed explanations of specific manipulations. However, the actual collection and evaluation of your data will impact the format of your results presentation. Consider the following: Data Collection: 1. Consider what type of information you will be gathering before you begin the experiment. In other words, read the experiment and determine what information will be used for later evaluation. 2. Determine how you will record your data. Data will usually be recorded in a tabular format. 3. Consider your independent variables (the variables you manipulate). This may be duration, voltage, tonicity, molarity, or a combination of these and/or other factors. 4. Consider your dependent variables. This usually is the response of the preparation, specimen, or tissue. Reactions may include volume change, voltage, force generation, or a combination of these and/or other factors. 5. If you have enough people working with you, assign one person to write the data down. Often the person manipulating the equipment will not be able to see immediate reactions, so assign one person to manipulate, and one to observe. The observer should communicate clearly and immediately to the person recording the data. 6. Record the data systematically. If you are recording over time, maintain constant increments of time. If you are recording voltages, try to vary the stimulus voltage in consistent increments. 7. Record information clearly and make sure your data is labeled. You may have difficulties when you are evaluating your data if labels are not clear. Evaluation of Data: 1. If you have collected numerous data points, determine if they can be statistically manipulated. Averages and standard deviations are the primary concern for this lab. 2. Determine if more information can be obtained from your available data, e.g., you may be able to determine conduction velocities, force of contraction, synaptic delay, or other factors. 3. Compare your results to the results obtained by other members of the class and to any published results. 4. Include the results of any statistical tests that you have used to determine the significance of the data. Presentation of Data: Data should be presented in a clear and concise format. This is usually limited to tables and/or graphs. Tables Tables should be clearly labeled. This includes a general label or title of the table, labels for each column, and labels for each row. Table A.1: Stimulator Voltage Calibration Stimulus Voltage (Volts) 0.1 Signal Voltage (Volts) 0.1 0.5 0.5 1.0 1.0 5.0 5.0 10.0 10.0 Stimul. Units should be presented along with the values (see Table 1). Graphs A graph usually presents a series of data points in a manner that is more readily understood than a chart or a table. The graph represents two variables. The dependent variable is usually presented as the vertical (or Y) axis, which is referred to as the 'ordinate'. The independent variable is plotted along the horizontal (X) axis, which is referred to as the 'abscissa'. For example: 1. Put the stimulus voltage on the x-axis and the response of the muscle on the y-axis. 2. Often running or consecutive time is recorded on the X-axis (e.g. minutes of exposure to a chemical). 3. The variables should be clearly identified along their axis. 4. Units for each variable should be written as consistent intervals and be clearly identified. 5. The graph should have a title and be clearly drawn. 6. Connect all consecutive points. 7. Graph only data points for which you have data. The only exception to this is if you are describing a statistical trend such as a correlation or regression. 8. The graph should appear neat, clean, and easily understandable. Examples of Graphs Signal Duration - Oscilloscope(msec Graph 2: Stimulation During Calibration 60 60 50 50 40 40 30 30 20 20 10 10 Graph 6.2 0 0 0 5 10 15 20 25 30 35 Stimulus Duration – Stimulator Fig. A.1: Example of a well labeled graph. 0 5 10 15 20 25 30 35 Oscill. Fig. A.2: Example of a poorly labeled graph It is not appropriate in the results section to draw comparisons of the data to known information. Save this evaluation for the discussion. The results section will be graded based on the accuracy of the reporting as well as the presentation of the data. All graphs and tables should be accompanied by a concise figure caption that includes enough information that the graph can stand alone and be understood. Some things to include in your captions: n values; what error bars represent; etc. Discussion (12 points) This portion of the laboratory report should critically consider the results obtained in light of prior data from the field. Are the results in variance or in agreement with known information? If so, why? If not, why not? It is important to look not only at the rationale of the experiments performed, but also at the techniques utilized, the skill of the experimenters, and other factors that may explain differences or similarities between the data and the expected results. This section should go over each treatment and explain, using citations, the reasoning behind the phenomena that are observed in the experiment. It would not be unreasonable when writing a laboratory report to include a short paragraph summarizing what was learned by the student from both methodological and conceptual standpoints. Conclusion (8 points) This section describes what the lab demonstrated - not just a rewrite of the introduction. Summarize the results and their relevance to the "big picture.” Do the results illustrate any important biological phenomena? Did the experiment serve its purpose and/or should further experiments be performed. It will be a brief summary of your findings and conclusions, but not a discussion of whether this was a fun lab or not. It is most certainly not an opportunity to complain about the quality of the equipment or the laboratory exercises in general. Literature Cited (2 points) You must have a minimum of three references in addition to your lab manual and textbook. All of your additional references should be peer-reveiwed. This means that they are published in peer-reviewed journals like Science or Nature. The UNT library grants access to many journals and they can also be found using search engines such as: GoogleScholar; Jstor; Web of Science; or Scopus. If you cannot gain access to a paper, the library also provides interlibrary loans through their ILLIAD portal. Physiology journals use many different formats for citing the scientific literature; therefore, there is no specific model to use in laboratory report writing. It is certainly expected that once a style is chosen, it will be used consistently throughout the report. Refer to any of the physiology journals, choose a format, and the use it. Other important points to keep in mind: (1) do not cite any references you have not read and (2) make sure that nay statement in the body of the text that is not your original idea is credited to the appropriate reference at that point in the text. In order to avoid plagiarism, you need to do two things when you take information from an original source: 1. Cite the original source. 2. Either put the ideas from the original source in your own words, or use quotation marks around the words from the original. The former is preferred. Example: This is the original sentence from the journal: The altered ratio between glycolytic and oxidative enzyme activities found in skeletal muscle of individuals with NIDDM suggests that a dysregulation between mitochondrial oxidative capacity and capacity for glycolysis is an important component of the expression of insulin resistance. This is the reference at the end of your paper: Simoneau J.A., Kelley D.E. Altered glycolytic and oxidative capacities of skeletal muscle contribute to insulin resistance in NIDDM. J. Appl. Physiol. 1997;83:166–171. This is the proper way to cite the original: The oxidative capacity in skeletal muscle, which is mostly dependent on mitochondrial function, is directly correlated with insulin sensitivity (Simoneau and Kelley, 1979). This is also proper, but not preferred. Do this only if you can’t come up will another way to reword the original. And we do mean can’t, as in, it is not possible, and not just that you don’t know how to reword the original: “Dysregulation between mitochondrial oxidative capacity and capacity for glycolysis is an important component of the expression of insulin resistance.” (Simoneau and Kelley, 1979). This is plagiarism. You will receive a zero on your paper for doing this: Dysregulation between mitochondrial oxidative capacity and capacity for glycolysis is an important component of the expression of insulin resistance (Simoneau and Kelley, 1979). This is absolutely plagiarism. We will not even feel bad about giving you a zero for this: Dysregulation between mitochondrial oxidative capacity and capacity for glycolysis is an important component of the expression of insulin resistance. Note that you must understand the original material before you can reword it. If you don’t understand the original, you should not be citing it. In Addition This is a general checklist for technical writing / grammatical grading Points will be deducted for the absence of the following: • Correct Title page • Page numbers • 6-15 typed (double-spaced) pages • All requested graphs, charts, and calculations • Titles for graphs & labels for axis, columns, and/or rows • Units for values on graphs • Concentration amounts of solutions used • Drawings, set-ups • Proper definitions for abbreviations Points will be deducted for the presence of the following: • Run-on sentences • Stream-of-consciousness thinking • 'We performed...", "I did", "The TA said...", etc (with the exception of the Methods section). • Spelling errors (use spell check, a dictionary, your manual) • Copying the lab manual or textbook There are 50 possible points for each lab report, and each section lists the points. Please note the importance of “Results” and “Discussion", this is where you get an opportunity to think about what you have learned. Four points a day will be deducted for late lab reports!