Contents
As a civil engineer, materials form the basis of what you do. Understanding material properties can help you make design decisions. Consider the road you drive on every day. Is it concrete or asphalt? At some point, an engineer had to ask, "How do those materials behave?" The answer to that question can be read in a book or developed through tactile knowledge in a lab. Testing materials and writing lab reports familiarize you with materials' properties.
Lab Reports are factual presentations of test results done in a materials lab. Typically, lab reports discuss materials and procedures as well as describe the details of a test. As a student, you'll write lab reports not only for a passing grade, but to learn from the observations you make. As an engineer in industry, you'll read many lab reports. Whether or not you write lab reports in industry depends on the company you work for and your position there.
Project notebooks record your tests and include information about the procedures you followed and your findings, as well as the successes and failures during a test itself. Notebooks also help you remember an test's details. If several weeks or months have passed since you actually completed an experiment, reading your entries from that time as you write your report will help you remember the details.
Readers may or may not know the details of a lab report. You shouldn't assume that they know a test well enough to fill in the report's blanks or that they know anything about the actual lab. To help you describe your lab thoroughly, assume you're writing for a peer in your class, a student who knows what the instruments are, but who doesn't know any of the details of what you're doing. Or, assume you're writing for design engineers who will use your information on a design project. They may not be familiar with all the terms, but if you list the standards, they can research the information.
Different types of lab reports are written for various situations. One such situation is an engineer must know the properties of three samples, so he sends the samples to the company's lab. A day later, he receives a slip of paper with his project's number on it and the results of the lab test. Since he already knows what procedures were used to test the samples, he does not require a formal report.
In school, instructors inform you of the data your lab reports should include. In industry, the amount of detail included in a lab report depends on who your readers are and how they will use the data. Most companies have strict requirements about the types of lab reports produced.
Internal lab reports are those written for use within a company. These reports are less formal than external reports because typically, the reader is a fellow employee who already knows the methodology and equipment used. Internal lab reports are result-oriented, that is, they present only the results of a test and don't necessarily have a specific format.
External lab reports are those written for use outside a company. These reports are more formal than internal reports because typically, the reader is a client who doesn't know the methodology or equipment used. External lab reports have a specific format, determined by the company, and include methodology, equipment and results sections. These reports are often confidential because a client pays for the report and, therefore, the data is theirs.
Lab reports, like other kinds of writing, have an organized format. The format depends on how the report will be used and what headings your readers expect to find. For example, in industry, a design engineer reading a report may be concerned only about a test's results and not the procedures or equipment used. On the other hand, a peer in your class reading your report may need to know what equipment you used and how you conducted your test.
Most lab reports follow a general format. However, you may be required to use different headings or to present your data in a different order. You may also be required to include or exclude specific information. Be sure to check with your instructor before using the format depicted here.
Transmittal letters often accompany reports and inform readers of a report's context. Typically, the letter includes information not found in the report. For example, when turning in a lab report, you would include the report's title, what assignment it fulfills and the due date. Check with your instructor to determine whether or not you should attach a transmittal letter to your report.
A lab report should always include a title clearly identifying the lab. A title should be descriptive and accurate, but not wordy, verbose or too terse.
The following are examples of strong titles:
The following are examples of weak titles:
Readers may expect, and require, a list of all the equipment used in a test. This list includes the equipment's name, as well as the equipment's number. Listing your equipment ensures that you use the same piece of equipment throughout a test. Check with your instructor to determine whether or not this information should be included under its own heading or with Procedures/Methodology.
Under the Procedures/Methodologies heading, you should describe each step of the lab test. You might also document your goals and the steps taken to accomplish those goals. To determine which heading to use, Procedures or Methodologies, check with your instructor.
In the Procedures/Methodologies report the steps, including any preparations, followed during a lab test. You should also document your goals and the steps taken to accomplish those goals. The materials and equipment you used may or may not be included here.
Procedures/Methodologies are extremely straightforward and typically written in the past tense. Here, you should not document the findings of a test -- that is, the results of a test. Instead, explain exactly what you did to get your results.
ASTM, The American Society for Testing and Materials, standards should be included under the Procedures/Methodology heading. These standards inform readers about how materials and samples were handled before testing. They also include materials' properties. The site below does not list standards, but it describes the ASTM organization and provides contact information.
American Society for Testing and Materials
Under the results heading, you should report what you found. Here, you may or may not include data interpretations. Some readers expect interpretations, or conclusions, to be a separate heading. Check with your instructor for what to include in your results.
In the results, document the test's outcome(s). Here, tell your readers what the test measured with exact data. You may also include calculations or equations.
Be brief when writing your results. If a lab has more than one finding, report the findings under separate subheadings. Typically, in the results, you present the numerical data of your findings. Be sure not to include details about how you performed a lab. Instead, report only the outcome(s). For example, "The results of the three tests are x, y, and z."
If you are required to interpret your data here, explain how you arrived at those results. You should also include why any data may be incorrect, such as odd occurrences during the test.
Under the conclusions heading, you should comment on the outcomes of a test. Here, you might also speculate about the implications of the results or even about the methods used to obtain the results. Some readers may not expect conclusions. For example, design engineers reading a report may interpret, or make conclusions, about results themselves. As a student, you may need to interpret, or make recommendations about, the results for your readers.
Under the conclusion heading, interpret the lab's results. If the results are correct, provide the reasons why. If the results are incorrect, discuss what went wrong. The conclusions also speculate about the implications found or even the methods used to obtain results.
Your conclusions should note what was good or bad about your test. If the results are not exactly what you expected, propose reasons why your results turned out as they did. When you comment on procedures, ask yourself questions such as what are the advantages of this method compared to other ways? What are its deficiencies, or difficulties compared to other ways?
Lab reports may or may not include references. If you use information from the course textbook, cite it as a reference. You should also cite any standards used from ASTM, The American Society for Testing and Materials, or ACI, American Concrete Institute. Check with your instructor to determine which reference style you should use.
Graphics provide illustrated information to readers. In general, graphics are designed to make it easier for readers to understand your report. Deciding when to insert a graphic depends on the information you need to convey. For example, as you're writing your report, you find yourself struggling to describe a complex concept. Fitting your description within a few paragraphs is impossible, so you decide to create a graphic. Often, graphics are useful when concepts, designs, or processes are too complex or cumbersome to describe in written or oral form.
Lab Reports in Industry
"Lab reports are done in industry because engineers need their materials tested. The purpose of commercial labs is to produce data, and often junior engineers work in these labs and write reports to clients. Also, engineers read lab reports throughout their careers. One way to become a discriminating reader is to write lab reports yourself. This way, you come to understand how the data evolves. Now, that doesn't mean you have to be a great novelist to read a novel, but by producing lab reports in school, you practice gathering and presenting data. "
Lab Report Format
"Lab reports done in school have similar general categories as those in industry. Typically, in industry, lab reports are highly company-specific. That is, companies have specific procedures to follow. When I worked for a company, we used a particular form to present specific types of data. We even had it down to the color, brown on buff! Otherwise, the general content was pretty standard."
Handling Samples
"With most testing, the question, "How was the sample handled before the lab?" often arises. Since handling can affect results, this information is necessary. For instance, lunar soils are tested in a vacuum because the moon's atmosphere is a vacuum. Well, were the soils kept in a vacuum from the minute they were taken from the moon and brought to earth? Were they exposed at all? Accounting for how samples were handled tells you whether or not standard procedures were followed and provides explanations for any strange results."
Calibration Errors
"Log books are a good place to record calibration information. You should always note when the last time a piece of equipment was calibrated because this is a common source of error. For example, your equipment hasn't been calibrated in over ten years. Because of this, it's off five pounds all the time. You need to know this. If you're on a diet, you want to know that your scale is five pounds off, so why wouldn't you want to know that your equipment is off? "
"Another source of error is not using the same piece of equipment every time you perform a test. For example, you're measuring the distance between two marks with a pair of dial clippers. Midway through the test, you set the clippers down. If you use another pair to continue the test, and that pair is off even a little bit, you've introduced a source of error. "
Good Results
"Good results depend on how well you follow the lab procedures. Not only do you have to produce accurate, precise numbers, but you also have to do a good job writing your report. Describe every detail and make conclusions and observations about your results. If you don't get the numbers you want, write about what you did and why you think the numbers aren't what they should be. It's easy to say, "My results are accurate," but more difficult to admit that your results are not accurate. Overall, you should understand how the test works and interpret why the results appear the way they do. "
Bad Data
"Always report all data, even if it's bad data. If one or two points are off, acknowledge those. Perhaps the lights flickered because of a power surge. Whatever the situation, try to explain why. If you have no explanations, write that, but remember to acknowledge the bad data."
Interpreting Data in Industry
"Lab reports produced by internal labs, those within a company, are more likely to include data interpretations. Lab reports produced by external labs, those outside a company, usually do not include data interpretations. This is because an external lab does not want to take on the legal responsibility of telling an engineer what to do with the results. "
Internal and External Lab Reports
"In permeability testing, samples are typically cured. Curing involves placing the samples in plastic bags and exposing them to humidity. Some labs have temperature controlled rooms. In situations where a temperature controlled room is not available, the sample is placed in a cooler filled with water. Now, with an internal report, employees know the company's standard operating procedures. They know whether or not a temperature controlled room is used; therefore, this information is not included in the report. With an external report, clients may not know how a sample is exposed to humidity. The lab report should inform them of this."
Dawn Kowalski. (1994-2024). Civil Engineering Lab Reports. The WAC Clearinghouse. Colorado State University. Available at https://wac.colostate.edu/repository/writing/guides/.
Copyright © 1994-2024 Colorado State University and/or this site's authors, developers, and contributors. Some material displayed on this site is used with permission.