Successful Lab Reports
A lab report is neither a term paper nor a scientific paper. Your report needs only a small amount of background information to give context to your own experiments or observations. On the other hand, while a lab report must have the structure of a scientific paper, it has a different audience and purpose. Your lab report is written to your Teaching Assistant, who already knows all about the work, to show that you understand the process and significance of the experiment. In contrast, a scientific paper is written to fellow scientist to present and discuss new information and ideas.
Why did you study this problem?
The Introduction gives the background to the work, starting with the broad context of the study and leading up to the hypothesis-the question studied, or the pattern sought.
You need to be able to choose relevant facts from the scientific literature, paraphrase them, and reassemble them into your own logical sequence, citing the sources to support each statement. Don't use your lab manual as sole source!
Introduce the methods and then the hypothesis. Outline scientific purpose(s) and/or objective(s). Never write that the objective was to 'learn the technique' or 'to measure this or that.'
2) Materials and Methods
What did you do? How did you do it?
In this section you will describe how and when you did your work, including experimental design, experimental apparatus, methods of gathering and analyzing data, and types of control.
Using your lab manual, handouts, and notes taken during the lab as a guide, describe in paragraph form the experimental procedure you followed. Be sure to include enough detail about the materials and methods you used so that someone else could repeat your procedure. A Generally, this section attempts to answer the following questions:
What materials were used?
What did you find?
In the results, you present your observations and data with no interpretations or conclusions about what they mean. A well-written and well-organized results section will provide the framework for the discussion section.
- Record all your results, using complete sentences, usually in
the order the observations were made.
- Tables and graphs should be used to supplement the text and to present the data in a more understandable form.
- The written text of the results section may be as
short as one sentence summarizing the highlights and directing the reader to
specific tables and figures.
- Include results that went "wrong" or were unexpected. This
may be useful information for someone trying to repeat the experiment.
- Use both words and numbers to describe your results, and use
- Use past tense to describe your results.
- Sample or detailed calculations for a lab report
### Tables and Figures
Tables and figures are often used in a report to present complicated data. Use the following guidelines to incorporate them effectively.
What does it mean? How does it relate to previous work in the field?
Explain what you think your data mean.
The Discussion answers the question. What do the results mean? It is essentially an argument about hypothesis based on the results. Since all the experiments or observations (presumably!) relate to the hypothesis in question, you must in the end draw your conclusion as to whether the hypothesis is supported. Although you could discuss results 1, 2, 3 in order, you will find that many comments either refer to several results or compare two or more results. You can more usefully organize the Discussion into a number of smaller questions:
1. What is your interpretation of the results, in light of the hypothesis and the published literature?
2. What are the significant sources of error in the results?
3. Therefore, how reliable are the results?
4. Do the results support the theory (or hypothesis)?
5. What changes in procedure would give better results; what additional experiments would help support or refute the theory (or hypothesis)?
Remember that whether your experiment worked as planned or deteriorated into complete chaos, you can write a good report.
The key section in the report is the Discussion, because it is where you show that you understand what should have happened and what did happen.
You should start the Discussion by stating your interpretation of the facts, in as positive a way as you can (without exaggeraing !), perhaps comparing or contrasting them to the literature. Only then should you tackle reliability and errors. Never start the Discussion by lamenting what wet wrong; consider the strengths of your data first.
You should freely admit a failure to get results; show that you understand what might have gone wrong. Notice that there is an important difference between negative results and a failure to get results.
The point of examining the error is to evaluate the results. Do not assign blame or assume any guilt.. even if you or your lab partner did something really stupid! Give a cool scientific explanation.
Finish the Discussion by drawing your conclusions and relating them to the Introduction. Don't make grandiose claims for a modest experiment. You don't have to pretend that your experiment or observations advanced science, and it looks silly if you do. And don't conclude that what happened was that you learned how (how not!) to do the experiment. Address the hypothesis. If appropriate, suggest how to improve the experiment, or what additional experiments would be helpful.
Leave the reader with a positive message. This is the end of the text of your report, and you want you TA to feel that the report is complete and satisfying. The worst possible way to end is just to stop at the end of a litany of errors. One good way to end is to return to an idea in the Introduction, especially one relating to the hypothesis.
### Assessing the results : Notes for the Discussion
Sources of error
Your data will have various errors which need to evaluate. The obejective is to discover the reliability of your data, the extent to which they can be trusted to tell you about scientific reality. You are analyzing after the fact.
Accounting for the sources of errors has nothing to do with assigning blame.
Do not blame yourself or other for what went wrong. Simply consider the sources of error and the extent to which they affect the data.
Here are some potential sources of error.
Errors in measurement
Errors in recording or recopying
Errors in computation
Differences from published procedures
List the changes and sources of error and try to decide for each if it would have a major or a minor effect on the results- or no significant effect - and in which direction the results would change, if at all. You need to know something about the process studied to make such judgments.
6. References & Literature cited
Also called "Literature Cited" or "References Cited," this is a list only of papers and resources actually mentioned (cited) within the report. (NOTE: A "Bibliography," on the other hand, refers to a list of all materials used to get background knowledge on a subject; you will not usually be required to include one in a scientific lab report.)
Scientific lab reports are written for the sole purpose of sharing information. If readers want more information about something, they need to be able to find the exact place it was originally written. References also give credit to the person who did the work and provide your work with authority.
- The reference list is provided on a separate page at the end of the report.
- Remember that ALL information within the report that is not your original work or ideas should be referenced (even if not quoted directly, but paraphrased or summarized - quotations are rare in scientific writing).
- Reference your lab manual, textbook, and any journal articles used.
1. SUCCESSFUL LAB REPORTS A Manual for Science Students, Christopher S. Lobban & Maria Schefter