WRITING A LABORATORY REPORT SCIENCE 101: THE EARTH SYSTEM Format:
All laboratory reports must follow the guidelines and format listed below:

Use 8 1/2 x 11" paper
Use a word-processor for all sections of reports
Staple all pages together in proper order
Correct spelling
Italicize or underline all scientific names of organisms
Write in the first person and use the past-tense
Use complete sentences and proper grammar
Show the title of each section of the report
Sentence and paragraph structure and grammar must be sufficient for effective communication of your thoughts.

Title:
The title states the subject of the laboratory. From your title, a reader should be able to predict what was tested in your investigation. The title summarizes information presented in the Introduction and Results section of the report. A title should consist of a few well-chosen words, ten or less, that accurately reflect the scope of your report.

Introduction:
The Introduction sets the framework for the entire report. In the Introduction explain to the reader the purpose of the laboratory. You may include some background information that is relevant to your question of study, explaining why the question or topic is of significance.
The second part of your Introduction is a statement of your hypothesis(es). Hypotheses are educated guesses that you propose as a tentative answer to the question(s) you are investigating. The hypothesis is written as a statement, not as a question or prediction. State your hypotheses as null hypotheses. For example, you might hypothesize that "the pH of water in a closed container that holds a fish does not change over time." Remember that your hypotheses are based on the knowledge that you have before doing the experiment, they are not just guesses. Your hypotheses need to be based on facts you have learned from lectures or literature.

Methods:
Include a Methods section in your laboratory report if you are asked to do so. The methods section includes a concise description of the materials, procedures, and equipment used. It should clearly describe the experimental situation, the control situation(s), and the type of observations you made. You need to explain your methods in enough detail that another person could repeat the experiment after reading your report. Do not include the rationale for your work in this section. Also, be sure to report your procedure in the past-tense rather than as a set of instructions to your reader. Use explanations to state your methods rather than "cookbook" instructions (e.g., Add 1 ml of solution to beaker A, add 5 ml of solution to beaker B, etc.) The questions below may help you with your writing:

What techniques were used? Would you be able to repeat this experiment based on the methods described in yur report?
How many individuals or test items were examined, i.e., what was the sample size? Do you think this sample size is adequate?
When were the samples taken? Should they have been taken at specific time intervals?
If an experiment was conducted, what factors or variables were held constant?
Were controls necessary for this experimental design? If so, were they provided for in each experiment?
Was the study replicated? If yes, can you tell how many times?
Which factors might affect the outcome of the study? Did the you consider them?
Do your methods test the null hypothesis(es) stated in your Introduction?

Results:
In the Results section state what the data and analyses show. Do not explain why you think your data did or did not support your hypothesis(es). Many papers are valuable for their results, although the interpretation of results (given in the Discussion section) may be completely wrong and may change with further study. Results can often be reported most effectively in the form of one or more graphs or drawings. Think about what would be the most effective way of presenting your data so that the reader can easily determine what the data show. All figures and tables must have a number and legend. Be sure to indicate whether or not the data reported are single readings or averages. Where appropriate, all results must be reported using the correct units (e.g., cm, ml, g, etc.). In addition to presentations of your data, a written description of the results is necessary in which you summarize the results illustrated in each Table or Figure. If you present data in a report, you must make it clear to the reader what those results show. The description should point out trends or inconsistencies, but should not include explanations or opinions.

Discussion
The discussion section is where you attempt to explain your results and relate them to the hypothesis(es) you posed in the Introduction. Interpret your results in light of your own knowledge and information in the literature. Consider the following questions:

What did you expect to find, and why?
How did your results compare with those expected?
How do you explain any unexpected results?
How might you test these potential explanations?
What is the significance of your results relative to the general topic that you studied?
What are the main scientific principles demonstrated by your results?

Do not use the word "prove" in your discussion. Your results will support, verify, or confirm your hypothesis, or they will negate, refute, or contradict your hypothesis; but the word prove is not appropriate in scientific writing. If your results differed from what you expected or from others in the class it does not mean that they are to be discarded or are in error. They ARE your results and need to be discussed. If in fact you determine that your data are probably in error or otherwise different from those of others, the data still comprise your results. Your discussion should include alternative scientific explanations for your results. Unforeseen difficulties with a procedure that may have affected your data should also be described here with statements of their possible effects on the data. Finish your discussion with statements of the conclusions that you drew from your results.

Future Work:
State an experiment that you believe would be a reasonable "next step of study" given the results of your experiment. Explain briefly what you would do and what significant new information you would gain from doing that new experiment. Be sure to state how the new experiment would be of value in that field of study. For example, in the fish and Elodea experiment, pH may change very little due to co-occurrence of photosynthesis and respiration. You might propose an experiment to specifically address the question: "At what rate do Elodea use carbon dioxide?" Class results certainly raise the question of why Elodea appears to use so little carbon dioxide. Addressing the question of how much carbon dioxide Elodea use would be a logical "next-step" for that topic and would help explain changes in pH, or lack thereof, in the original experiment.

Example of a Laboratory Report