How to Write a Lab Report – General Chemistry Edition

Objectives

  • Use the scientific method to formulate and test hypotheses in lab experimentation.
  • Develop a hypothesis for a scientific experiment.
  • Identify the control, independent, and dependent variables for an experiment.
  • Conduct literature research on concepts discussed in the laboratory.
  • Utilize scientific journals as a source of information.
  • Complete an analysis of laboratory experimental results (data) that will include calculations of accepted value, experimental value and % error design.
  • Complete a critical analysis of laboratory experimental findings.
  • Perform an in-depth analysis of a laboratory experiment, including statistical and graphical analysis.
  • Explain the sources of bias, percent error, and uncertainty in experimental analysis.
  • Draw conclusions based on experimental data.
  • Identify sources of error and explain their impact on experimental data.
  • Communicate lab procedures, observations, and results in the form of laboratory notebook, written reports, and verbal presentations effectively.
  • Interpret and analyze qualitative observations and quantitative results, incorporating graphs and tables as appropriate.

Introduction

A critical aspect of conducting laboratory experiments is effectively communicating your findings and conclusions in written form. Reporting the results of an experiment and providing a critical analysis of the data is one of the easiest ways to accomplish this goal. This form of writing is called technical writing.

Technical writing involves describing what occurred as clearly and concisely as possible. Technical reports tell the reader what they will see presented in the report, outline the data/evidence, and finally tell the reader what they have seen.

While most people do not have to write about scientific findings in real life, it is essential in today’s world to communicate effectively with others in written form. All areas of employment, from health care to construction, require effective communication between co-workers. Reporting your laboratory findings will help you develop writing and communication skills that will benefit your career after college.

You will be responsible for completing laboratory reports this semester. Your instructor will tell you which specific experiments you will be reporting on. The semester schedule lists the due dates for these assignments. Remember from the lesson on The Scientific Method that reporting your findings is the final step of the scientific process. The work you do in the lab is your research and your work. Present it with pride.

While you may have worked in the lab with a partner to complete this experiment, you must write your lab report in your own words. While working with your partner to determine an experiment outline and analyze the data is okay, you need to write your own lab report. Writing a lab report with your partner, with each of you submitting identical copies or strikingly similar versions of the report, is plagiarism.

The use of AI to write any part of a laboratory report is strictly prohibited in this class and will be considered a violation of the academic honesty policy.

The format for writing lab reports for this course is based on the general outline for writing a scientific paper. Please watch Video 1.0 below to learn how scientific journal articles are structured.

Video 1.0 – How scientific journal articles are structured.

Please note that not ALL of the items outlined in Video 1.0 are required for this class. I have outlined the requirements and expectations for writing lab reports for this course in the following sections.

Voice

Lab reports should generally be written using third-person voice. Do not use pronouns when writing your lab report. For example:

Instead of writing (first person):

We added 10mL of hydrochloric acid to the beaker and stirred until the reaction was complete.

Write this instead (third-person) :

Ten milliliters of hydrochloric acid was added to the beaker and stirred until the reaction was complete.

Additionally, the experimental procedure should be written in the past tense, since it was already completed, and all other sections of the report should be written in the present tense, since they are happening now.

Report Requirements

The following is a list of requirements regarding formatting and electronic submission of your assignment. You will receive a zero on your submission unless it meets these criteria.

  • All submissions are typed, and all tables and graphs are produced using a spreadsheet program like MSExcel.
  • All tables/figures/graphs are electronically inserted into the body of the report in the appropriate section. DO NOT take a photo/screenshot of your data table and paste it into the report.
  • All report sections are labeled (see below for sections required).
  • The assignment is one continuous document. Therefore, your report should be contained in just ONE document.
  • The lab report should be submitted electronically via the assignment folder on Brightspace. Save the document as a MSWord file (.doc or .docx) or pdf. If I cannot open the submitted file, you will receive a zero for the assignment.
  • The student completed the report on an experiment assigned by the instructor and conducted in this course. You do not need to write an experiment or find another one to report on.

If you are unfamiliar with using word-processing programs such as Word and Excel, you must learn for this course and your future career. Most employers expect employees to utilize basic word and spreadsheet processing software effectively. Riverland offers computer courses to help you learn how to use these programs. In addition, online instructional videos for MSWord and Excel are available. More information on the availability of technology to assist you in this course is provided in the course syllabus and on Brightspace.

Required Report Sections

A detailed list of the sections and information that must be included in your laboratory report is outlined below. Your instructor may also provide specific information for the experiment you report on at the end of the experimental procedure.

Title Information

At the top of the first page of the report, provide the following information:

  • The title of the experiment – The title says what you did. It should be brief (aim for ten words or less) and describe the main point of the experiment or investigation. An example of a title would be: “Effects of Ultraviolet Light on Borax Crystal Growth Rate”. If you can, begin your title using a keyword rather than an article like ‘The’ or ‘A’.
  • Your first and last name
  • The date the report was submitted or completed.

Introduction / Purpose

The introduction explains the concept discussed in the lab. It should introduce the reader to the chemical concepts being applied in the laboratory. In other words, if the lab is about chemical changes, the introduction should contain information about what a chemical change is and how to recognize one.

The introduction should also include a sentence stating the hypothesis (what you expected to happen during the experiment) and the dependent and independent variables being tested. The hypothesis should address the entire experiment (all parts). If each part of the experiment is very different, it may be necessary to develop a hypothesis for each part of the experiment.  Developing one general hypothesis that covers all parts of the experiment may also be possible.

The dependent and independent variables should also be identified in the introduction to the report.

  • The independent variable is what is manipulated or changed by the researcher. It causes the results.
  • The dependent variable is the response that is measured in the experiment. It is the effect of the experiment and is dependent on the independent variable.

If an experiment has multiple parts, please identify each part’s dependent and independent variables. Depending on the experiment, it may be possible to make a general statement regarding the dependent and independent variables (i.e. rather than state each chemical as a dependent variable, they could be referred to collectively as the reactants).  These items must be expressly indicated in your report. Information on developing a hypothesis and identifying dependent and independent variables was discussed in The Scientific Method laboratory activity.

Since we are learning to use scientific literature in this course, you must also include one peer-reviewed scientific journal article as a reference when writing your lab report. I will provide one that applies to the experiment. You can use this journal, or you can choose a different one. The journal article you choose should provide more information about the experiment or topic your lab report is written over. This article should be utilized in your introduction section and properly cited at the end of the formal lab report as a reference. I will supply the APA citation with each journal article I provide on Brightspace.

The introduction needs to be in your own words. Do not copy the introduction from the experimental procedure and paste it into your report. If you do this, you will receive a zero for the report. The introduction demonstrates that YOU understand the chemistry concepts behind the experiment, not that you copied it from another source.

Experimental Procedure

List the equipment used and describe the steps you completed during your investigation. Write it as if you were giving directions for someone else to do the lab, and be detailed enough that anyone could read this section and duplicate your experiment. You may copy the experimental procedure directly from your laboratory manual if you like, but all other sections of your report must be in your own words.

This section must be formatted the same as all of the other sections of your report. Do not scan or otherwise copy the results section and paste it into the report unless it can be formatted the same as the rest of the report. Points will be deducted if this section is not formatted as described at the beginning of this document (see Report Requirements for more information). You can include figures/diagrams in your experimental procedure if they help better explain how to complete the experiment. Simply take a screenshot of the figure and paste it into your procedure. If the figure comes from the experimental procedure provided by your instructor, there is no need to reference it since the experimental procedure is always cited at the end of the report. If you take a figure from another source, you will need to cite it.

Results Section

This section should include the numerical data obtained from your procedure, which can be presented as a table. Data encompasses what you recorded when you experimented. It’s just the facts, not any interpretation of what they mean.  Your tables should be

  • Be neatly organized, with all rows and columns appropriately labeled.
  • Have a title and be numbered. For instance, the first table in your report should be numbered “Table 1,” etc.
  • Briefly summarized in your report. DO NOT just provide a data table with your results.  You also need to briefly talk about what your results were.

If you completed a table during the laboratory activity to document the data collected, this table must be included in the report. Be sure to title all tables and organize it (complete with labeling any columns or rows) to ensure the data can be easily read and understood. All tables should be formatted as described at the beginning of this document (Tahoma or Times New Romans 10pt). Tables should be produced using a word processing program such as MSWord or Excel.

In some lab reports, we may also collect and analyze the classroom data. If we do this, you are expected to include a data table for the classroom data in your lab report following the above guidelines.

Calculations

This section should also contain any formulas you used and calculations you completed based on your data. There is no need to include sample calculations, just the formulas you used to process your data.

Discussion Section

This section discusses your results and how they tie back to the chemical concept discussed in the experiment. Below are some items to address in your discussion:

  • Explain the chemistry of your results. Why did they occur as they did?  This should tie back to the concept being explored in the experiment.  Your explanation should demonstrate that you understand the discussed concept and how it applies to your results.
  • Calculate the percent error for your results based on the known values.
  • If your experimental data is incorrect, you need to talk about what the results should have been.
  • Identify sources of error for the experiment (i.e., mistakes you might have made while conducting the investigation or why the experiment didn’t work and what you could have done to improve the outcome.) There are ALWAYS sources of error, even if your experiment turned out as expected.
  • If we collected classroom data on a spreadsheet, you also need to include an analysis of this data using mean, median, range, and standard deviation. Include not only the statistical values you calculated for the class data but also what they mean regarding the validity of the data collected. A video demonstrating how to calculate the mean, median, range, and standard deviation for a data set is available HERE.
  • Determine if the data (both yours and the classroom data) support the concept being discussed in the experiment. Explain why it does or does not support this concept.
  • Include any figures/graphs necessary to explain the meaning of your experimental data. You are only required to include a graph/figure in your lab report if we created one as part of the lab experiment/postlab assignment.
    • Figures and graphs are not always necessary to produce a good laboratory report, but they are often the best way to present data or show trends and explain the data’s meaning. Graphs and figures must both be labeled with a descriptive title. Label the axes on a graph, including units of measurement. The independent variable goes on the X-axis. The dependent variable (the one you are measuring) goes on the Y-axis. Figures and graphs should be included in the body of the report and then referenced and introduced in the text of the report. The first figure is Figure 1, the second figure is Figure 2, etc.

NOTE:  If the laboratory experiment required you to draw a figure or graph to analyze your results, that figure or graph must be included in your report.

Video 2.0 demonstrates how to graph in Excel.

Video 2.0 – How to graph in Excel.

Conclusions

The conclusion is a single paragraph summarizing what happened in the experiment, whether your hypothesis was accepted or rejected, why you accepted/rejected it, and what this means for the experiment. This should act as a summary statement for your report.

References

If your research was based on someone else’s work or if you cited facts that require documentation, then you should list these references.  The experimental procedure should ALWAYS appear in the references section and the scientific article you used in the introduction.

NOTE:  If references have not been properly cited, this will be considered plagiarism and can result in a zero for the assignment.

In this course, you must properly cite your sources in APA format. The Purdue Online Writing Lab (OWL) website and the University of Auckland at New Zealand Quick©ite website provide information on how to cite sources in these formats and additional information regarding plagiarism.

Other Report Guidelines

The following are a list of general guidelines for completing your lab reports:

  • There is no length requirement. However, your lab report should be long enough to cover everything but short enough to be interesting.
  • Part of the grade will be on how clearly the student presented their data and explained its meaning. Write the report as if the person reading it has never done the lab or taken a chemistry class. You are presenting your research in the lab report. YOU are the expert on what you write.
  • Review your report before submitting it to ensure that the format of the report is correct/consistent. All the text should be the same font type and size. Use standard margins (1″ all around) throughout the report. This college paper should appear polished, aligned, and professional.
  • Proofread your lab report for grammar and spelling mistakes. Use superscripts and subscripts appropriately when discussing chemical formulas and ions.
  • Submit your report in one of the following formats: .doc, .docx, or .pdf. If you submit another file type and I cannot open it, you will receive a zero for the assignment.

Please note plagiarism is not tolerated in this class. Your submission must be your original work. If plagiarism is discovered in any other section of your report, you will be reported to the college for cheating and receive an F in the course. Please see the Riverland Student Code of Conduct for more information on academic dishonesty.

An example lab report and the experimental procedure it was written on can be obtained by clicking HERE. This lab report does not contain classroom data or the statistics information discussed in these guidelines. A copy of the rubric for this assignment is provided on Brightspace. Please read both documents to understand better how to complete this assignment correctly.

Please contact your instructor if you have any questions.

The rubric for each lab report can be found on Brightspace under Assessments → Rubrics → Title of the lab report.

References

Indiana University Bloomington. (2023). How To Write a Lab Report. Libraries Indiana University Bloomington. https://guides.libraries.indiana.edu/c.php?g=992698&p=7182653

Norfold State Writing Center. (2021). Tip Sheet: Science Writing and Lab Reports. Norfold State University. https://www.nsu.edu/Academics/Academic-Resources/Writing-Center/Resources/Tip-Sheets-Files-2023/TIP-SHEET-Writing-Lab-Reports_NSU-Writing-Center.aspx

Parry, B. (2020, June 16). Scientific Reports – Fuse School [Video]. YouTube. https://youtu.be/U8vjuVSq3bs?si=pV4rzSGPJkcu5gr5

Purdue University. (2021). Chemistry Lab Resources (for CHM 1XX and 2XX Labs).  Purdue University. https://guides.lib.purdue.edu/c.php?g=352816&p=2377942

Note to Educators

These guidelines were written General Chemistry courses and science classes intended for science majors. A simpler lab report format designed for introductory-level chemistry classes is available here.

This page was published on January 4, 2024 and last updated on July 30, 2024.

©Catherine Haslag 2024. All Rights Reserved.