Lab reports provide a model for research papers, which are the most frequently written documents in scientific fields. Lab report structure varies by field; however, the goals of a lab report remain consistent: 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 researchers’ 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.
think about it
You will complete two Touchstone Lab Reports in this course that provide an opportunity to reflect on simulation activities and to practice your written scientific communication skills. In the lab reports, students are expected to demonstrate an understanding of the scientific method, developing hypotheses, following procedures, and experimental error. A lab report template is provided for you and will be the foundation for the Touchstone. After completing the lab report template, you will upload the report for grading. Please see the Touchstone pages for specific details.
term to know
Lab Reports
A written document that describes an experiment, the reason for the experiment, the results of the experiment, and the implications of the experiment
2. Lab Report Structure
A well-written lab report demonstrates the researchers’ 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:
Hypothesis
Background and Theory
Methods and Data Collection
Results and Observations
Discussion, Conclusions, and Implications
hint
You will use this common structure when you prepare lab report assignments in this course.
2a. Hypothesis
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.
hint
To learn more about how to form a proper hypothesis refer to the lesson on the Scientific Method.
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 the 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, for example in weather forecasting models.
In order to ensure that data are 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 fail to support a current model and a new model must be developed!
big idea
By applying the major steps of critical thinking, we can relate our observations to a scientific model that helps us better understand our world.
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 an important public health question. Overweight and obesity is a growing trend among adults. With increasing body weight, there are increased risks of heart attack, stroke, and death. The link between body weight and these risks is thought to be increased blood pressure. So, does blood pressure increase with increasing body weight?
A hypothesis makes a claim and then predicts an outcome, often presenting as an if-and-then statement.
EXAMPLE
This hypothesis is well stated:
"If body mass index increases, then mean blood pressure should also increase."
EXAMPLE
This hypothesis is poorly stated:
"Does a person's BMI affect their blood pressure?"
terms to know
Hypothesis
A tentative explanation of observations that acts as a guide for gathering and checking information.
Model
A representation created by the scientist to explain real-world phenomena that cannot be directly observed because the variables are difficult to manipulate.
Scientific Reasoning
A type of critical thinking that creates a greater understanding of a topic through testing observations against already established models and theories.
2b. Background and Theory
The second step of a lab report is to provide the reader with any background theory, previous research, or formulas needed to understand the problem you are investigating. This will set the context for your investigation. Ask yourself, what information does the reader need to know to understand why you are conducting the investigation?
In this portion of your lab report, you will also explain in detail the previous models that have been used and tested. This information sets up the need for your investigation. 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 about obesity and blood pressure, let’s examine the background information.
EXAMPLE
"The World Health Organization (WHO) estimates that 31% of the world’s population has cardiovascular disease, including high blood pressure. Of this subgroup, 80% have experienced heart attacks or strokes; that is approximately 2 billion people (Landi et al, 2018). Furthermore, the WHO considered a primary risk factor for cardiovascular disease to be obesity. To this end, over the past 35 years, the prevalence of obesity has doubled worldwide (Arroyo-Johnson and Mincey, 2016). Among adults aged 18 years or older worldwide, 11% of men and 15% of women were obese in 2014 (Arroyo-Johnson and Mincey, 2016).
Obesity is most commonly measured by the body mass index (BMI), which is the body weight in kilograms divided by the square of the height measured in meters [BMI = kg/m²]. This measurement does not account for body fat distribution and has recently been questioned as a reliable indicator of obesity. So, does blood pressure actually increase with increasing BMI? This investigation was undertaken to address this question."
2c. Methods and Data Collection
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.
hint
This list does not have to be in complete sentences but should be accurate and complete.
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 that another researcher could 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 detail 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.
hint
To learn more about how to form a proper hypothesis refer to the lesson on the Scientific Method.
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 of obesity and blood pressure, our experimental procedure may be presented in the following manner:
EXAMPLE
“Adults 18 years and older were recruited for this study from various public places such as shopping malls, health exhibitions, and sporting events. They answered a health questionnaire to obtain the following data: informed consent, age, gender,
and lifestyle habits (smoking, eating habits, and physical activity). Body height was measured with a stadiometer, body weight was measured with a standard medical weight scale, and blood pressure was measured with an electronic sphygmomanometer. BMI and mean blood pressure were calculated. There were 7,900 participants in the study.”
terms to know
Experimental Procedure
The specific steps and techniques used to conduct an experiment.
Experimental Methodology
The research design and methods used to manipulate variables to establish a cause and effect.
Validity
The extent to which a measurement or result is accurate and measures what it claims to measure.
Reliability
The overall consistency of a measurement. The results of the measurement produce the same results under the same conditions.
2d. Results and Observations
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 support 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 bell curve. A normal distribution begins by plotting 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 standard deviation 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 is far outside the normal distribution and is typically thrown out and considered a point of error.
Errors can be random, systematic, or blunder errors. Random errors occur due to 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 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 obesity and blood pressure example, we may report our findings as follows:
EXAMPLE
"According to the BMIs of the study participants and WHO categories of obesity, 38% were classified as overweight, 14.3% were classified as obese, and 0.7% were classified as severely obese.
The mean blood pressure of the study participants indicated that 11.8% had elevated blood pressure and 3.2% had hypertension.
The mean blood pressure increased significantly and linearly with increasing BMI. (see image below). Mean blood pressure increased by about 11 mm Hg from a normal BMI to a severely obese BMI."
Mean blood pressure vs. Mean BMI in adults 18 years and older. The color of the data points indicate the WHO BMI categories of obesity: blue = healthy, yellow = overweight, orange = obese, red = severely obese. The horizontal dotted lines delineate the categories of blood pressure as determined by the American College of Cardiology and American Heart Association. Source: adapted from Landi et al, 2018
Note that only summary or representative data (graphs, figures, tables) should appear in the results sections. Any raw data or calculations should appear in the Appendicies (see below).
terms to know
Evidence
Data that support a claim.
Normal Distribution
A bell curve that provides the probability distribution of a random variable.
Mean
The average of a set of data.
Standard Deviations
The amount of dispersion from the mean in a set of data.
Statistically Significant
The probability that a result from experimental data is attributed to a specific cause. The higher statistical significance the less likely a result is due to chance.
Outlier
A data point that differs significantly from other data points.
Random Error
An error in experimentation that is a result of chance.
Systematic Error
An error in experimentation that can be clearly identified and controlled.
Blunders
An error in experimentation that is a result of carelessness or mistakes.
2e. Discussion, Conclusions, and Implications
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 from 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 obesity and blood pressure example, a discussion paragraph may look similar to:
EXAMPLE
"The present study shows that mean blood pressure values are linearly correlated with BMI. In particular, obesity status was associated with elevated blood pressure and hypertension. Furthermore, body weight and BMI are easily measured and the linear relationship indicates that they are simple and effective tools for screening the risk of hypertension, especially in public settings."
3. References and Appendices
References will include an itemized list of any resources, readings, or manuals you used to design, justify, or 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 your 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
Here is an example of references for our obesity and blood pressure example:
EXAMPLE
Landi F, Calvani R, Picca A, Tosato M, Martone AM, Ortolani E, et al. Body mass index is strongly associated with hypertension: Results from the longevity check-up 7+ study. Nutrients. 2018 Dec 13;10(12):1976.
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 the heart cells are contained in appendix A”. You will list appendices in chronological order as they are referenced in the lab report.
think about it
Citing your research and references is an important step in the lab report process. You will not be expected to provide references in your Touchstone Lab Reports for this course because all of the information you need to complete the simulations has already been provided for you in Labster.
terms to know
References
Information that directs a reader to identified work that was cited, referred to, or mentioned in a text.
Appendices
Graphs, pictures, reports, notes, or tables that provide additional material related to a document.
summary
In this lesson, you learned how to construct the components of a well-written lab report. Although the structure of a lab report may vary, the goals and components will remain consistent. You explored how to write a hypothesis and use scientific reasoning to document and evaluate your observations. You learned the importance of providing the background, theory, research, and formulas needed for your audience to understand your experiment. You learned how and why you need to carefully document your methods and data collection, describing the experimental procedure chronologically and maintaining validity and reliability in the experimental methodology. You learned how to record your results and observations, including the key scientific data that supports your claim. You examined how to discuss your conclusions and implications to help your audience understand the meaning and importance of your results. Finally, you learned how to document your references and appendices.
