NPHS Science Department
Formal Lab Report Format
Most lab reports will be informal, just a tabulations of data and answers to discussion questions.
Each six weeks, 1-2 lab reports will be formal. The idea of a formal lab report is to bring
together the results of the experiment in a clear and complete way. The tone should be serious.
The report should be 1-3 typed pages with accompanying plots, tables and calculations. Hand
calculations, equations and diagrams are acceptable.
Your lab report should tell a story: why you are doing the lab (purpose); how you did it
(method); a summary of the outcome (data and calculations); your results and a discussion of
sources of error (conclusion.) Organize you report using the headings and descriptions below.
TITLE PAGE: Name of experiment, your name, partner’s name, course, date (Interesting
graphics and images are always appropriate.)
PURPOSE: In your own words, briefly explain the overall goal of the experiment. Mention the
underlying principles, theories and/or methods involved. Do not include lengthy information
about methods, data or results found in other sections of the report.
METHODS: Describe the approach you used to accomplish the goal of the lab. Include an
explanation of the procedure, equipment, techniques and theory used to achieve your purpose. A
person who understands chemistry should be able to read this section and know what you are
doing. Include and explain any important chemical and mathematical equations not
mentioned in the PURPOSE. This section should be at least one long paragraph.
DATA/OBSERVATIONS: Organize all data and observations you collect in the lab in a neat
and orderly form using tables where appropriate. Label all tables and data clearly. Give short
descriptions of the tables and data that put each in the context of the experiment. Always use
correct units and sig figs.
CALCULATIONS: Show how calculations are carried out by including one neatly presented
sample calculation. First, give the equations used and show how your values are substituted into
it. Present all sample calculations in a logical sequence. Finally, organize all results in neat plots
or tables as appropriate. Graphs should be neatly labeled with important features highlighted.
If theoretical results are available, complete a quantitative error analysis, including
calculations of error, which are appropriate for this lab (see Error Analysis in the General
Information section for calculations of percent error, deviation, relative deviation, etc.) If
experiments are not quantitative, this section may be omitted.
CONCLUSION: In this section you will evaluate the results of the lab. This is where you
discuss whether the underlying theory was demonstrated (or not demonstrated.) To this end, a
three-paragraph model works well.
First, list your experimental results and any calculated error. Compare your results with the
purpose you stated earlier.
In the second paragraph discuss any sources of error. Explain discrepancies between actual and
expected results in terms of errors in measurement and technique. Be sure to distinguish
between a mistake (an avoidable mishap such as spilling some of the solution) and an error
(implicit in any measurement you take.) What are some specific sources of error and how do
they influence the data? Do they make the values larger or smaller than they should be? Which
measurement was the least precise and how would that influence your results?
In your final paragraph discuss what you would do differently if you were to repeat the
experiment and wanted to obtain better precision and/or accuracy?
DISCUSSION QUESTIONS: Answer any discussion questions included in the lab. If you
have already answered a question in your earlier lab write-up, refer to that section of your report.
Finally, read back over your lab report and make sure it accurately and impressively
communicates all the hard work and thought you put into the lab. Remember, you may be
submitting these lab reports to your college chemistry department for credit.
For your first quarter formal lab reports you will be allowed to submit the report for a re-grade if
you revise it according to feedback.
Help may be found at www.ncsu.edu/labwrite