Guidelines for Writing Lab Reports

Though the specific requirements for each professor/TA differ, lab reports as a whole follow a general format. Scientific writing is generally done section by section, and is formal and concise. Grammar and good writing are still important, but it’s very different than writing in the humanities. Flow, language and cohesiveness are not all that important; what you are looking for is the incorporation of all the necessary information in a detailed but to the point document. Additionally, formal lab reports are nearly always written in the third person.

The following sections AND their content are subject to change. The specific requirements for each TA are different, but this is a general guideline to follow. It will help if the student has the sheet laying out what sections the particular TA is looking for, and what they want to see in each section.


  • Should summarize the purpose of the experiment — the title importance varies depending on the course. For general chemistry, it is fine to give the name of the experiment and the title taken from the lab manual, but other courses may require specificity.
  • Include a heading with your name, your partner’s name, date, lab section and experiment number.


  • Contains a summary of background information relevant to the experiment
  • Describes the general purpose of the experiment: what you’re trying to find, how you’ll find it, and why it might be important.
  • Information for this usually comes from reading the lab manual. If outside research was done, it should be cited appropriately

Experimental Procedure

  • In paragraph form, briefly summarize the steps performed in the experiment
  • Should be concise enough that someone with a general chemistry background could conduct the experiment in the same way.
  • All measurements should be quantified and all equipment should be mentioned
  • A brief chronological description in the past tense, passive voice of exactly what steps were taken in the experiment
    • Ex. (past tense): “10 ml of solution were added to the beaker”, rather than “Add 10 ml of solution to the beaker”
    • Ex. (passive voice): “10 ml of solution were added to the beaker” rather than “we added 10 ml of solution to the beaker”


  • A calculations sheet (on which you show sample problems with work) is usually given out in lab and is a required part of the lab report.
  • Make sure all data is labeled with appropriate units both on the sheet and throughout the lab report. TAs love to take off points for this.


  • TAs generally don’t want to see every number you’ve collected throughout the experiment.
  • Often one large table of important calculated values will suffice (important values = numbers you’ve had to calculate, including averages-or measurements you’ve taken).
  • If there is data that can be graphed (anything with multiple trials or recordings; example = time v. temperature) it will usually be required.
  • Graphs should be done in Excel, with separate graphs for separate trials.
  • Graphs are sometimes their own section. It is not uncommon to have four or six graphs for one lab report.
  • Generally, no explanations or interpretations of the graphs will be required in this section, but they can be used in the discussion at the end of the lab report.

Results and Discussion

  • Summary of what you found and how you found it.
  • Include observations from the experiment (color changes, smells, and phase changes- basically anything you can see, smell, hear or feel)
  • Analyze and interpret the collected data ? what do your results mean in terms of the experiment?
  • Address the theory demonstrated in the experiment and explain if the results support the theory or not
  • Include error analysis: if your results were not near what they should have been, explain what happened or what might have happened. Be sure to address how this error could be eliminated in future experiments
  • If you have to include information from outside sources, this is where you should do it. The information should help to explain the meaning of your results or experiment, and should be cited using APA format.

Lab Questions

  • The lab manual usually asks four or five questions at the end of the experiment.
  • These are usually separate from the discussion section, and should be answered in their own section of the lab report.