Writing a Lab Report

M. George

Physics Dept.

Southwestern College

Topics• Introduction• Why write a lab report?• Who should write a report?• What is the background for a report?

– The data record– Preliminary theoretical predictions– Preliminary data analysis– Planning a report

• What needs to be done prior to writing a report?– Data analysis

• Study data distribution• Evaluate independent measurements• Elaborate theoretical predictions

• What needs to be in a report?– Tables– Graphs– Figures

• How does one write a report?– Introduction of the report– Body of the report– Conclusion of the report– Reference list

• Comments

Introduction

• Why write a lab report?

• Who should write a report?

• What is the background for a report?

• What needs to be presented in a report?

• How does one produce a report?

Why write a lab report?

• Practice for possible manuscripts you will write later in life.

• It is an opportunity to develop a holistic perspective, and an appreciation for the work of others on the team.

• It allows you to revisit what your team did during the experiment, and emphasize those things that were of clear importance.

• It helps you build the intellectual framework of science that can serve you later in life, even if you do not become a scientist or an engineer.

Who should write a report?

• On your team, there will probably be one or more people with obvious writing skill and ability. Shouldn’t these people write the report?

• There is no perfect answer to justify why everyone should write separate reports.

• However, it does build self-reliance, an ability to communicate, and an opportunity to put everything together and appreciate the efforts of each person on the team.

What is the background of the report?

• Ordinarily, there will be an extensive background to draw on in writing the report that will make the process easier:– The lab instructions, the course text and lecture, and other references

that are available from the library or internet provide a background rich in information.

– You will have a data record from the experiment. If this is well-organized, it can be very helpful in writing a report.

– In preparing to do the experiment, and during the experiment, you will probably having carried out some theoretical analysis to make predictions.

– In the course of doing the experiment, you probably carried out some preliminary data analysis.

– Prior to endeavoring to write the report, you probably carried out some planning. For example, preparing an outline can be very helpful.

• The more prior work that you have done, and the better that it is organized, the easier the writing process will be.

What needs to be done to write a report?

• Data analysis– Statistics

• Averages• Standard deviations• Propagation of errors

– Data distributions– Elaborate theoretical predictions

• Comparison with theory

What needs to be in a report?• Tables: average values, percent errors, etc. One usually does not put raw

data in a report, unless there is an especially good reason.• Label tables, and provide succinct informative descriptions of what is in a

table. Include units.• Describe tables and their importance in more detail in the report.• Graphs: curve-fitting, histograms, etc., i.e. visual descriptions. Need to be

labeled and described like tables. Do not clutter graphs (three different types of description, e.g. three curves, is usually the maximum number for clarity).

• Figures or diagrams: These can be useful to promote clarity. Sometimes a schematic illustration with fewer details than something more realistic like a photograph can be very valuable. Similar remarks apply with respect to illustrations as to tables or graphs.

• As a general rule: Do not include something you do not plan to discuss in the body of your report. Include what is needed and no more.

How does one write a report?

• Overall, spelling and grammar are important. Use a spell-checker if available. Use punctuation for clarity and to avoid ambiguity. If English is not your native language: Do your best. Most technical reports, worldwide, are now written in English.

How does one write a report? (cont.)

• Introduction of a report– Briefly review or survey what is in the body of the

report.– Provide a perspective on your report by citing relevant

references (listed in the Reference section). The lab instructions, at a minimum, should be mentioned. Discuss briefly the importance of these references, any limitations, and ways in which your work may have modified or gone beyond these references.

How does one write a report? (cont.)

• Body of the report• You should have at least the following sections:

– Theory: include sufficient background to follow the computations and predictions made in the experiment. Hopefully, this is not just a regurgitation of the lab instructions.

– Procedures and description of what your team did. Avoid merely repeating the lab instructions.

– What was learned? What were the main results? What mistakes were made? Were you able to correct them? Do you see how to correct mistakes you were unable to correct at the time of the experiment?

– Of course, you may need other sections, particularly if there are certain questions your instructor or the lab instructions pose that need to be answered. Then you may need to have a problem section.

How does one write a report? (cont.)

• Conclusion of the report• The conclusion of the report should be very brief, no

longer than one or two paragraphs, usually.• The conclusion is similar to the introduction in structure,

but much more succinct:– Briefly summarize what was covered in the body of the report– Make clear the main items you learned from the experiment and

state the principal results.– If you see any improvements that could be made in the

experiment, or any further experiments or investigations that might be worthwhile, point these out

How does one write a report? (cont.)

• Reference list

• List all references used. At a minimum you should have the lab instructions.

• When you copy from a reference, make sure to make this clear by using quotation marks. (This avoids accusations of plagiarism.)

Comments

• Every instructor has his or her own style, and what we have pointed out here should only be taken as suggestions for a lab report.

• In general, the labs are an opportunity to develop some familiarity with the scientific method. This can be a useful framework to acquire, whether or not one becomes a scientist or engineer.