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Lab reports provide a model for research papers, which are the most frequently written documents in scientific fields. The structure of a lab report varies by field; however, the goals of a lab report remain consistent: to identify an area to explore, conduct an experiment, document your findings, and communicate the significance of your results.
A well-written lab report demonstrates the researcher's understanding of the concepts behind the data collected. Knowing the purpose behind the basic components of a lab report will assist you in organizing your ideas clearly and expressing your thoughts coherently.
A well-written lab report demonstrates the researcher's understanding of the concepts behind the data collected. Knowing the purpose behind the basic components of a lab report will assist you in organizing your ideas clearly and expressing your thoughts coherently. The following list is an example of a common lab report organizational structure:
The first step of a lab report is to state the hypothesis of the experiment. The hypothesis is a claim that answers a question or makes a prediction about an event that has not yet occurred.
In science, we are always working to develop a better understanding of our universe. Science uses models as a tool to improve future understanding based on current understanding. A model is a representation created by a scientist to explain real-world phenomena that cannot be directly observed because the variables are difficult to manipulate. The model can be of a physical item, like a molecular model, or it can be a representation of a concept, like evolution due to natural selection. Scientists develop mathematical models that use data from complex systems to predict change over time, like tectonic movements or global warming. Models also allow us to make predictions about events that have not yet occurred, like weather-forecasting models.
In order to ensure that data is not excluded or misinterpreted from the model, scientists use a process called scientific reasoning to document and evaluate their observations. Scientific reasoning, also known as critical thinking, helps develop better models of understanding by testing observations against scientifically established models. If the model holds true given the data, the model is supported. If the model does not hold true given the data, the model is rejected. Exciting science happens when an experiment provides data that fails to support a current model and a new model must be developed!
IN CONTEXT
In Section 1 of your Touchstone Lab Reports, you will be asked to describe the overall simulation objective and your hypothesis. Let’s practice how to use the steps of critical thinking to answer a question about polydactyly in cats.
Some cats have more than five toes on each paw, a condition known as polydactyly. Polydactyly is an observed trait that is found equally in male and female cats. Even though having more than five toes on each paw is rare among house cats, those cats with the polydactyly gene mutation always present with extra toes on one or more paws.
If we were to make a claim in the form of a hypothesis about the polydactyly mutation that we observe in cats, we would make a statement that answers a question or makes a prediction about the mutation. A hypothesis makes a claim and then predicts an outcome, often presenting it as an if-and-then statement.
EXAMPLE
This hypothesis is well stated: “If my polydactyl cat has kittens, then the kittens will have more than five toes on at least one paw.”
EXAMPLE
This hypothesis is poorly stated: “The polydactyl gene mutation always impacts offspring that carry it.”
The second step of a lab report is to provide the reader with any background theory, previous research, or formulas needed to understand your experiment. Ask yourself, what information does the reader need to know to understand the importance of your experiment and data?
In this portion of your lab report, you will also explain in detail the previous models that have been used and tested that support or are related to your hypothesis. These previous models are often referred to as your reasoning or theory.
IN CONTEXT
In Section 2 of your Touchstone Lab Reports, you will be asked to introduce relevant background knowledge on the simulation topic. You will find research and references in the lab manual included with each simulation. Include supporting details from the lab theory to support the answers you list in the lab report.
Sticking with our example hypothesis—predicting polydactyly in a cat’s offspring—we may want to present previous data that has been reported regarding polydactyly in cats. Our reasoning or theory may be presented in the manner below.
EXAMPLE
“Prior research by Lettice, Hill, and Devenney in 2008 found that polydactyly in cats is a congenital autosomal dominant trait caused by a mutation in the ZRS gene. Further research also indicates that polydactyly in cats often only presents on the front paws (Axel, 2013).”
The third step of your lab report will cover your experiment in detail. You will provide the reader with a list of equipment and materials used.
You will then describe the experimental procedure in chronological order. The experimental procedure will state all the steps of the experiment in order as they actually happened. It is essential for you to record the procedures as they occurred even if the order was not consistent with the description in a manual or how you thought it was supposed to happen. This is so another researcher can replicate your experiment if they are testing for similar outcomes.
EXAMPLE
If you were supposed to expose a chemical to red light for 5 minutes and you actually exposed the chemical to red light for 7 minutes, you need to document an exposure time of 7 minutes.If you deviated from your plan or standard procedure, be sure to document why. Deviations should be limited and only occur in situations where scientific discovery is needed.
EXAMPLE
Sticking with our chemical example, perhaps there was no change to the chemical in 5 minutes of light exposure, so you changed your exposure time to 7 minutes, this would be an acceptable deviation.Deviations due to intentional error or carelessness by the researcher are not acceptable deviations.
EXAMPLE
Let's say our researcher intended to expose the chemical to red light for 5 minutes. However, the researcher stepped away to calibrate an instrument and instead exposed the chemical to red light for 7 minutes. It would not be acceptable to use this data. As the researcher was not present to observe the results at the 5-minute mark to justify a deviation from the planned procedure.In addition to the experimental procedure, you should also report your experimental methodology. The experimental methodology provides details about your sample size, variables, statistical analysis, and methods used to account for error. Choosing the correct experimental methodology for your experiment helps the reader evaluate your experiment for validity and reliability.
Validity and reliability are concepts that readers can use to evaluate how well your experimental methodology and experimental procedure can test your hypothesis.
Validity is the extent to which your experiment results measure what they are supposed to measure. You can check the validity of your experiment by correlating the results with other measures of the same concept or other established theories.
Reliability is the extent to which the results from your experiment can be repeated by another researcher under the same conditions. Reliability can be checked by comparing the results across time and across different parts of the experiment.
In order to minimize error and increase the reliability of data collected during experiments, measurements must be taken multiple times. The more times you collect the measurement, the less likely you will have errors. However, replicating measurements takes time and money; as a result, we typically only repeat measurements two or three times in a lab course setting.
IN CONTEXT
In Section 3 of your Touchstone Lab Reports, you will explain each step you completed in the simulation including the equipment and techniques you used. What was the experimental procedure you followed?
Continuing with our example hypothesis—predicting polydactyly in a cat’s offspring—our experimental procedure may be presented in the manner below.
EXAMPLE
A female Maine Coon with a Hemingway ZRS mutation was placed in a pen with a male Maine Coon without the Hemingway ZRS mutation. The female Maine Coon was given 1 cc of progesterone to regulate estrus cycle and increase sexual receptivity and fertility. The cats were kept together for 60 days to capture two full heat cycles. The female Maine Coon was administered an ultrasound upon completion of the breeding time. Ultrasound confirmed a pregnancy of 25 days gestation. The female cat was sequestered and fed a diet of high-calorie, high-protein Hill's Science Diet twice daily at the rate of 12 oz per feeding. On the 43rd day following breeding, the female cat gave birth to six kittens (five of which were female and one of which was a male). The kittens were then examined for the polydactyl mutation and data was recorded.
The fourth step in writing a well-constructed lab report is to report your findings. Results and observational data are usually reported in tables, graphs, and visual figures. Graphics should be clear, concise, and well-labeled. Evidence is the scientific data that supports the claim we have made.
Any significant results should be called out in verbal form. You can capture the reader's attention by providing a sentence or two that discusses the calculation, the trends, and any special features.
Statistical significance is built upon the notion of a normal distribution or a bell curve. A normal distribution starts with the plotting of the mean, or average, of a data set, which assists in representing a large collection of numbers with a single digit. The standard deviations are separations in increments below (−) or above (+) the mean that lead to separations between 68.2%, 95.4%, and 99.7% of the data set, with 68.2% representing one standard deviation, 95.4% representing two standard deviations, and 99.7% representing three standard deviations. The standard deviation is important in research as it reflects the degree of variation or dispersion in the data from the central mean.
EXAMPLE
A normal distribution bell curve showing 68.26% centered between 1 standard deviation, 27.7% between 1 and 2 standard deviations, and 3.77% between 2 and 3 standard deviations.
Statistical significance is the probability that a result will fall on the distribution curve at or below a certain percentage, usually 1% or 5%, represented as P 0.05 and P 0.01, respectively. Statistical significance indicates the likelihood that a result did not occur by simple chance alone, and can be used to determine whether a hypothesis should be rejected or accepted.
The further a measurement is from the mean, the more likely it is an outlier. An outlier is a measurement that differs significantly from other data points and is typically thrown out and considered a point of error.
Errors can be random, systematic, or blunder errors. Random errors occur because of chance and can be a result of slight fluctuations in instrumentation, environments, or measurement technique. Systemic errors result in measurements that are different even when conducted under the same conditions. Systemic errors have a clear cause and can be eliminated. Blunders are errors due to the carelessness of the researcher and are considered outright mistakes.
IN CONTEXT
In Section 4 of your Touchstone Lab Reports, you will describe any obtained results from the simulation. Were these results expected or unexpected?
If we continue using our polydactyl cat example, we may report our findings in the manner below.
EXAMPLE
Upon visual observation of the Maine Coon cat litter, four of the six Maine Coon kittens exhibit the polydactyly mutation. This phenotypic expression was found on four of the five females within the litter. One female and the only male within the litter did not express the polydactyly mutation on any of their four paws. All four of the females with the polydactyly mutation had the mutation on their front paws. None of the polydactyl females had the mutation on their back paws. Three of the four females demonstrated polydactyly on their right front paws and not on their left front paws. One of the four polydactyl females demonstrated polydactyly on both their right and left front paws.
The number of females compared to males in the litter was unexpected as well as the number of females compared to males that exhibited the polydactyly phenotype. Because of the low number of kittens evaluated, less than 30, observations cannot be directly correlated to the breed as a whole. In addition, only phenotypic expression was evaluated, not the specific genotype of the kittens.
In the fifth step of a lab report, you will explain, analyze, and interpret your results. This portion should be written in paragraph format and should be written as a discussion of what is not obviously apparent in your data. Your conclusions should answer the question “What is the meaning of my experimental results?”
After you clearly explain your conclusions, you will then discuss any new questions that might be raised from the results. You will want to identify any ambiguities in the data, provide logical explanations for problems in the results, and account for any difference in the results and what you might have expected.
This is also where you will discuss any possible errors that could have occurred in human reporting, instrumentation, or in the environment. If you took steps to account for these errors, you will want to explain those steps and the limitations of your abilities to eliminate flaws in the experiment.
IN CONTEXT
In Section 5 of your Touchstone Lab Reports, you will describe the conclusions and implications if the simulation results. For example, how do your results relate back to the original purpose and your hypothesis? Were there any systematic sources of error that could have affected the results? What did you learn? What is the importance of these findings and how can you apply them to other real-world situations?
If we continue using our example of polydactyly in cats, a discussion paragraph may look similar to the following.
EXAMPLE
“Data indicate that a polydactyl cat will produce offspring demonstrating the polydactyl trait 50% of the time if mated with a cat without the polydactyl mutation (Allen, 2017). As expected, the experiment showed that a cat with the polydactyl gene produced at least one offspring with the polydactyl mutation. When bred with a cat without the polydactyl mutation, six kittens were born, four of which inherited the polydactyl mutation. All four polydactyl kittens expressed more than five toes on one of the front paws. This observation has previously been made by Axel in 2013. All four polydactyl kittens were female, despite prior evidence that polydactyly expresses evenly among males and females. There are several possible reasons that the polydactyl kittens were all female, including the fact that a larger percentage of the offspring group was female (83%). Further research should be conducted on the percentage of polydactyly offspring that express polydactyly on the back paws by sex and whether these rates change when mating occurs between two polydactyl cats.”
References will include an itemized list that directs a reader to any of the resources, readings, manuals, or works that were used, referred to, or mentioned in order to conduct your experiment. These items may include research articles, manuals, websites, videos, or reports. References are often used to justify the development of your hypothesis, the methodology chosen to conduct your experiment, and previous work that assisted in your interpretation of the results. Every field will have a preferred method for documenting references. Make sure you know what citation style is appropriate for your occupation.
Common styles of references are listed in the following table.
| Citation Style Abbreviation | Full Title | Field |
|---|---|---|
| APA | American Psychological Association | Social Sciences |
| MLA | Modern Language Association | Humanities |
| CMS | Chicago Manual of Style | History and Arts |
| APSA | American Political Science Association | Political Science |
| ASA | American Sociological Association | Sociology |
| CSE | Council of Science Editors | Scientific Disciplines |
| Harvard | Harvard Style | Economics |
| ACS | American Chemical Society | Chemistry |
| AMA | American Medical Association | Field of Medicine |
| IEEE | Institute of Electrical and Electronics Engineers | Engineering and IT Disciplines |
| NLM | National Library of Medicine | Field of Medicine |
| Vancouver | Vancouver Style | Medical Disciplines |
| Bluebook | The Bluebook: A Uniform System of Citation | Used in Political and Law Documents |
| OSCOLA | Oxford Standard for the Citation of Legal Authorities | Used in Political and Law Documents in the UK |
Appendices are graphs, pictures, reports, notes, and tables that provide all your raw data and calculations. Reports from instruments, calibration information, or bench notes should be provided in the appendices. When referencing these items in other portions of the lab report, you will just make a statement such as “Reports from scanning microscope are contained in Appendix E” or “Visual observations and images from Maine Coon kitten litter are contained in Appendix A”. You will list appendices in the chronological order of their reference in the lab report.
Source: SOURCE: THIS CONTENT HAS BEEN ADAPTED FROM https://openstax.org/books/biology-2e/pages/1-1-the-science-of-biology and https://openstax.org/books/introductory-statistics/pages/1-1-definitions-of-statistics-probability-and-key-terms
REFERENCES
Caulfield, Jack (2022). Scribbr: Citation Styles Guide. Retrieved 8.16.2022 from https://www.scribbr.com/citing-sources/citation-styles
