Traditional Lab Reports Main Page

Writing to Demonstrate Learning
Traditional Lab Reports

Overview
General Lab Report Format
Teacher Notes
Sample Scoring Guide
Examples of Student Work

Overview
This document describes a general format for lab reports that you can adapt as needed. Lab reports are the most frequent kind of document written in science classes, but are no longer exclusive to sciences. With the ever increasing emphasis on discovery learning, lab reports are becoming more common in other classes. Lab exercises are a chance for students to have "hands-on" experiences and to practice the skill of scientific thinking. While this skill is the backbone of science, scientific thinking can also be used in daily life to help draw valid conclusions from observations and data and is an important part of the curriculum in many subject areas.

A good lab report does more than present data, it requires a student to think in depth and detail about material and demonstrates the writer's comprehension of the concepts behind the data. Merely recording the expected and observed results is not sufficient. Students should also identify how and why differences occurred, explain how they affected the experiment, and show understanding of the principles the experiment was designed to examine. Bear in mind that a format, however helpful, can not replace clear thinking and organized writing. Students will need to organize ideas carefully and express them coherently. While labs for each class may differ slightly in mechanics or format, the goal of a lab report remains the same: document findings and communicate their significance.

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General Lab Report Format -Click here for printable handout-

Think of the report as a scientific essay. It will contain the the following sections:

Title
Purpose
Procedure - may be excluded from some labs
Data
Results
Discussion
Conclusion

A brief description of what each section should include is given below. You can adapt this format to the particular needs of your course.

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TITLE: The title should summarize, as specifically as possible, the subject of the lab.

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PURPOSE: A single, concise statement of the major objective(s) of the lab that answers one of the following: What question or questions is this lab exercise designed to answer? OR What is this lab exercise designed to show or prove? OR What hypothesis is this lab exercise trying to prove or disprove? Note: To make a hypothesis, you must be able to provide support for that hypothesis, based upon your knowledge or literature research. A hypothesis should be an EDUCATED prediction!)

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PROCEDURE: This paragraph should not be included unless you have been asked to explain your procedure. If asked, you should include the information necessary to allow someone to repeat what you did, such as:

What data was used? Include information about the data such as the data source (i.e. Internet, observations, models)
Include definitions of key terms and anything else necessary to understand exactly what was done.

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DATA: This is a record of all measurements and other observations encountered during the lab exercise.

Record data carefully and immediately. Do not rely on your memory! The most carefully made observations are not useful if you do not record them accurately. Always include the units of physical quantities.
You and your lab partner(s) should complete all the work and make all of the observations together. It is very difficult to write a good lab report if you have not done some part of the experiment! Do not copy the results of other groups unless instructed to do so: To do so will be considered plagiarism! If you and your lab partner(s) disagree about an observation, record your own.
Present the data in a way that makes it easy to discuss and to infer conclusions (Tables or graphs are often helpful!) Do not describe the procedure or discuss the data in this section -- just present your data!
Graphs will sometimes be required or helpful. These should be drawn on graph paper or with a computer. The horizontal axis should contain the independent variable (the one that is known), and the vertical axis should contain the dependent variable (the one that you are observing or measuring). Each axis must be labeled. The graph must be titled. The intervals on each axis must be consistent.

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Results: Separate from your lab notes, this section should contain a summary of the final data, presented in a form that is most useful for interpreting the results. A short paragraph should be sufficient, along with any relevant charts and graphs labeled will. Remember to title and provide legends for all graphs and tables. The graphs and tables should be comprehendable independently of their association with the text.

Results are usually dominated by calculations, tables and figures; however, you still need to state all significant results explicitly in verbal form, (i.e. Using the formula for slope, the rate of change of the data is V = 1.8m/s)
Graphics need to be clear, easily read, and well labeled.
Number and Title tables and graphs.
An important strategy for making your results effective is to draw the reader's attention to them with a sentence or two, so the reader has a focus when reading the graph.
In most cases, providing a sample calculation of each type is sufficient in the lab report.
Be sure to point out trends and identify special features.
State your key result in sentence form.

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Discussion: This is the most important part of the lab, as it is where you interpret your observations and results. For each conclusion you should discuss its significance and whether or not it seems reasonable. In addition, be sure that you answer any questions that were asked in the laboratory instructions.

You should infer conclusions from your data. For each conclusion, you should provide evidence from your data. Be sure to include a sample calculation of each type used.
Give explanations for and implications of any relationships observed. (When interpreting a graph, infer conclusions based upon the slope of the line or lines.
Support your ideas with specific, quantitative references to the results of your analyses. How do your observations lead to the conclusions you reached?
Were the relationships what you expected from the underlying physical principles? If a conclusion does not seem reasonable, can you find any error in your procedure which could have affected your results?
For each conclusion you should discuss its significance. Address any interesting questions you may have had as you were working through the lab exercises. In addition, be sure that you answer any questions that were asked in the laboratory instructions.
Can you make any generalizations? Why or why not?

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Conclusion: Summarize your results, the main points of your discussion, and how they relate to your stated purpose of the lab.

You are to restate all the conclusions that were made in the discussion section.
No discussion or explanation or speculation should occur in this section! (Do not use the words "because" or "since" or "therefore".)
It is a good idea to include how the main points of your discussion are connected in order to demonstrate the overall significance of your findings and the concepts you learned.
Please do not tell me how much you enjoyed this experiment or how much you learned from it. Just give me your conclusions!

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Teacher Notes

Before the lab, students should read through the instructions for the lab exercise. You may want to read the instructions aloud with the students first, especially for the first few lab experiences.
During the lab, encourage students to consider the answers to any questions asked in the exercise as notes for the scientific essay (lab report) they will be writing as they work through the lab.
Remind students that the brevity of the lab report requires that they attempt a concise writing style, touching only upon their most important observations and results. Nevertheless, they must also present as much supporting detail as is necessary to support their conclusions and allow the reader to understand the logic by which they were obtained.
Students will be tempted to change their initial hypothesis to fit the outcome of the lab. Remind students that hypotheses are educated guesses or ideas. When experimental data does not support the original hypothesis, it does not necessarily mean the hypothesis is wrong or needs changing, it only means that the data do not support it. It helps to have students turn in a written copy of their hypothesis before the lab begins.
Remind students to do the following, after the lab report is written:

Make sure their writing is clear. Have the student read it aloud to him/herself or a friend, does it make sense? Remind them to use the word processor spell-checker or a dictionary.
Check to be sure all the questions included in the lab exercise are addressed .
Check to be sure all pertinent plots, graphs, etc. are included and staple all pages of the lab report together.

Note on Verb Tense: Lab reports often create difficulties for students who struggle with keeping verb tenses straight. These two points should help:

The experiment is already finished. Use the past tense when talking about the experiment. (i.e. The objective of the experiment was...)
The report, the theory, and permanent equipment still exist; therefore these get the present tense. (i.e. The purpose of this report is...; The graphing calculator produces...; Boyle's Law states...)

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Sample Scoring Guide -Click here for printable handout-

Your lab report grade will depend on completeness, scientific accuracy and insight, organization, and writing skills. I expect lab reports to be written neatly and legibly in ink, or prepared using modern word-processing programs, and to follow the format of the handout you received in class. You will also be graded on: Your ability to complete the lab exercise (I will be watching...); Your thoroughness in cleaning-up afterwards (I will check...); And on overall neatness, proper grammar, and correct spelling in the lab report.

The point totals for each section are for a 100 point report. For 50 or 150 point reports points will be adjusted proportionally.

1. Title. (10 points)

The title should summarize, as specifically as possible, the subject of the lab.

2. Purpose. (20 points)

The Purpose should put the experiment into context and provide the reader with information necessary to understand the scientific basis of the experiment and the techniques used.

3. Data (25 points)

This section should include all raw data, including units, and appropriate graphs.

4. Discussion (30 points)

Discuss the experiment and the results obtained. This does not mean you simply report the results again, but rather interpret and discuss their significance. Include a section containing a summary of the final data, presented in a form that is most useful for interpreting the results and sample calculations of each type used. A short paragraph should be sufficient, along with any relevant charts and graphs labeled well. Remember to title and provide legends for all graphs and tables. The graphs and tables should be comprehensible independently of their association with the text. Significant results should also be stated explicitly in verbal form. If problems were encountered during the course of the experiment, how might they be rectified in the future? Are there any other things we could do to make this a better experiment or to more specifically address the initial question(s) posed? Are there any better techniques available that would allow one to more accurately generate data? Is there more than one way to explain the results? Your results may support your initial hypothesis, but there may be more than one conclusion that could be drawn from your results. Lastly, do not spend enormous amounts of time explaining data that cannot be explained!

5. Conclusion. (15 points)

Summarize your results, the main points of your discussion, and how they relate to your stated purpose of the lab. No discussion, explanation, or speculation should appear in this section.

6. Reference Citations

As required in all scientific literature, statements of fact, not considered "common" knowledge, must be properly referenced. Give complete citations of all literature cited in the report.

What's complete? Here are some examples:

Articles in Journals:

Marmur, J. 1961. A procedure for the isolation of deoxyribonucleic acid from microorganisms.
J. Mol. Biol. 3:208-218.

Articles in Books:

Coakley, W.T., A.J. Bates and D. Lloyd. 1977. Disruption of bacterial cells. p279-341. In A.H.
Rose and D.W. Tempest (ed.), Advances in Microbial Physiology, Vol. 16. Academic
Press, London and New York.

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Examples of Student Work

Example 1

Used in a unit on Fractals. Student pairs investigated drawings of various linear fractals to examine the following hypothesis: Is it possible for a geometric shape (fractal) with a finite area to have an infinite perimeter?

Example 2

A two-day enrichment activity on Chaos used in a series of Honors Algebra lessons on random and recursive iterations, and strange attractors. Student groups of three investigated the following hypothesis: Will repeated completely random data choices result in a recognizable, ordered pattern? The data was generated and tested using both manual and electronic means, then the results of the two methods were compared.

Example 3

Used in a unit on ratio and proportion. Student groups of three or four simulated the Capture-Recapture method of numbering a population used by Fish and Wildlife personal. Guiding Question: Is this an accurate method for numbering a population?

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