Perspectives on Lab Reports
Tom Siller, Civil Engineering
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."
"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."
"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 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. "
"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."