Writing practical reports
- What is the purpose of practicals?
- What is the structure of practical reports?
- Organising the practical report: how to use the sections
- General guidelines for technical writing
What is the purpose of practicals?
Practicals or experiments provide you with opportunities to explore certain aspects of professional practice of your course. This may involve you in:
- reading published information
- carrying out the experiment/gathering data
- collecting and organising data from the experiment and the published information
- interpreting the results
- communicating the findings by writing laboratory practical reports.
Through this kind of exploring you develop:
- techniques in collecting, organising, analysing and reporting data
- skills in the use of equipment
- judgements about procedures and the results of experiments
- insights into the relationship between theory and practice
- familiarity with how engineers and scientists work and report professionally on their work.
What is the structure of practical reports?
Each course area has its own requirements for the format and content of practical reports. Check your course information carefully and, if necessary, talk to your lecturer to ensure that you meet the guidelines.
In general, a practical report is made up of various sections, each containing specific information, as summarised in the following table:
Section of your report |
What each section tells your reader |
|---|---|
Cover page |
identifying information |
Synopsis/abstract |
main ideas in summary form |
Aim and introduction |
what you investigated and why |
Method |
techniques you used |
Results |
what you found out |
Discussion |
what the results mean and how they relate to theory |
Conclusion |
summary of findings related to the aim |
Appendix |
detailed information referred to in the report |
References |
source(s) of published information used in the report |
Organising the practical report—how to use the sections
Cover page —identifying information
The cover page identifies you and the report. In it you include required details such as:
- course
- title of the report
- your name and ID number
- date
- lecturer’s name.
Synopsis/abstract —main ideas in summary form
The synopsis/abstract is a brief summary of the report, approximately 70–100 words in length. In it you:
- state the aim
- mention the method used
- summarise the results and the discussion (include numerical information where appropriate)
- state the conclusion.
An example:
The experiment aimed to determine the head loss coefficient K and Le/D ratio for a series of pipe fittings and compare these with published values. The pressure drop across a variety of pipe fittings was measured for a range of flow rates. Results showed that as the Reynolds number increased from 30000 to 60000 the head loss coefficient for all fittings reduced by approximately 20 percent. Le/D ratios and K values do not remain constant for varying flow rates. This is contrary to predictions. The inaccuracies within the experiment may be reduced by updating and maintaining pipes and fittings.
Aim and introduction —what you investigated and why
The aim of the practical may be part of the introduction, or it may be required as a separate section. In the aim you briefly state the purpose and scope of the practical, but you do not include detailed information about the method used.
For example:
The aim of the practical was to determine experimentally the overall heat transfer coefficient of a tube in the tube heat exchanger and to examine the effect of varying fluid velocity on this quantity.
In the introduction you state what you investigated and give background information, including any relevant equations. You may include a brief reference to relevant theory and practice and predict the likely outcome of the practical. You may refer to published material.
An example:
Holman (1992) states that the overall heat transfer coefficient increases with increasing fluid velocity. This experiment was designed to confirm this relationship and to explore the differences between parallel and counter flow heat exchanger arrangements.
Sometimes in the introduction you include a hypothesis which is a prediction about results, using the information available at the time.
Examples:
The experiment was to test the hypothesis that the heat transfer coefficient increases with increasing fluid velocity.
Theory predicts that if the fluid velocity is increased then the heat transfer coefficient increases.
Method —techniques you used
In the method you set out the procedure you followed during the practical, specifying the materials and equipment you used and what you did with them. To carry out the practical you were probably given a set of detailed instructions in a laboratory manual or handout. They would have included directions such as:
Using the digital top pan balance, weigh a definite volume (100 mL) of planting mix into weighing boats.
You will be expected to incorporate these directions into the report in one of four ways. Do only one of the following:
Options for incorporating directions |
Example |
|---|---|
1. Attach the instruction sheet to the report. |
|
2. Refer to the instructions. |
‘The practical was carried out according to page 12 of the Laboratory Manual.’ |
3. Rewrite the instructions into a brief account of what you did. |
‘100 mL of planting mix was weighed.’ |
4. Rewrite the instructions into a detailed account which could be used to repeat your investigation. |
‘A definite volume (100 mL) of planting mix was weighed out into weighing boats, using the digital top pan balance.’ |
You should always record any variations from a standard procedure.
‘The volume of planting mix was halved for smaller samples, then adjusted for 100 mL.’
Labelled diagrams may be a useful summary of the method—for example:
Results —what you found out
In the results you describe your findings and observations. In this section you may:
- present appropriate raw data
- calculate results from raw data
- present derived results in tables and/or graphs as appropriate
- write a brief description of these results.
Present your results logically and concisely without interpretation or comment.
Raw data
You should organise your raw data into a clear, systematic format which could be a table or illustrations such as photographs and maps. If you have a large number of measurements or recordings put them in the appendix and include a summary of them in the
results.
Calculations
You may be required to include formula(s) and details of calculations to show clearly how you arrived at your final results. Explain the meaning of each symbol.
An example
Mass flow rate
M = 0.128 Ö D h Hg = 0.128 Ö 35 = 0.757 kg/s
(Where M is the mass flow rate, D h Hg is change in height of the mercury column.)
With a series of repeated calculations, show detailed working for the first calculation only, and then just the results of the others. Similarly, for long and complicated calculation procedures, you may include a set of sample calculations in the appendix. Present a summary of the derived results in the report.
Tables and graphs
Where appropriate, use tables and graphs to present your results.
- number tables and graphs in order
- give each a title
- include headings and units.
An example:
Table 1—Derived flow velocity in various pipes
Volume Flow Rate |
Resulting flow velocity (m/s) |
||
|
75 Schd 40 |
50 ID Plast |
80 ID Plast |
6.26 |
1.313 |
3.189 |
1.245 |
6.57 |
1.378 |
3.347 |
1.307 |
7.16 |
1.504 |
3.649 |
1.420 |
7.32 |
1.535 |
3.729 |
1.456 |
If graphing results, the choice of graph—eg. a histogram or line graph—will be determined by the type of data.
If you have more than one set of results, plotting them on the same graph allows for comparison. Label axes on graphs and plot clearly, using a set of symbols.
Written description
Summarise in words the key findings from your calculations. Where tables and graphs have been used, refer to them and the results they contain.
Example:
As the volume flow rate increases the resulting flow velocity also increases (Table 1).
Discussion and/or conclusion —what the results mean and how they relate to the theory
The Discussion and/or Conclusion is the key part of your report. It shows that you understand the practical and that you can critically evaluate your results. You should interpret your results by relating back to the aim and indicating how well the aim has been achieved. In the discussion do not repeat your results but explain what they show and what they mean, what is important about your results and why. Questions may be provided in your Laboratory Manual to indicate what points you need to discuss.
In the Discussion you should do the following:
- Relate your results to the current knowledge and practice outlined in the Introduction to show that you understand the theoretical basis of the experiment. Where relevant, compare your findings with previous studies, commenting on similarities and differences. You may refer to relevant literature. For example:
The generally accepted value for g is 9.81 ms -2 although there are global variations. The values for g polar and g equator are 9.8322 ms -2 and 9.7803 ms -2 (Tennant 1992). The value calculated from the experimental data is g = 9.85 ms -2 which approximates the generally accepted value to within 1%.
- Comment on any unexpected results or outcomes—for example:
This variation seems reasonable given the obvious inconsistencies in the data for t C and the accuracy of the measuring instruments which were used.
- Acknowledge any problems, limitations, inconsistencies or errors in results and suggest probable reasons. Sometimes a detailed ‘error analysis’ is required. For example:
The large error associated with this value can be attributed to the set of data for t C which does not show any trend demonstrated by t B and t A.
- Suggest further investigations or extensions of your experiment, if appropriate. For example:
Applying this approach and using the formula
T = 2 p Ö l/g
it would be possible to use the relevant value of g to calculate the period of the pendulum at any location e.g. at the summit of Mt. Kosciusko.
The Conclusion may be part of the Discussion or may be required as a separate section. In the conclusion you summarise your findings as they relate to the stated aim of the practical.
Although the accepted value for the acceleration due to gravity (g) for rigid bodies is 9.8 ms -2 , variations exist according to the geographical location.
Appendix —detailed information referred to in the report
Use the Appendix to provide extra, supporting information relating to your practical, such as:
- detailed or repetitive raw data
- charts, diagrams, computer programs
- sample calculations.
Number appendices Appendix 1, Appendix 2 etc. and refer to them in your report.
References —source(s) of published information used in the report
The reference list is a list of any sources you referred to in your report. The list is arranged in alphabetical order and includes full bibliographic details of the sources used in your report. For more details see 'Referencing'.
General guidelines for technical writing
When you write practical reports, be aware of accepted conventions or guidelines which apply to technical writing generally. Check with your lecturer regarding any specific requirements.
Standard of presentation
A written report should be of a professional standard—that is, well laid out, neatly presented and word processed if possible. Refer to your course’s guidelines for more specific requirements.
Technical terms
Show that you understand technical terms and that you are able to use them appropriately, for example:
The energy contained within a fluid is expressed as head, the unit being metres.
You may be required to provide definitions of technical terms or key words.
Active or passive language
Scientific and engineering literature has commonly used passive language — for example ‘A colour change was observed’ — rather than active language — for example, ‘I observed a colour change’. This has the effect of placing the emphasis on the experiment rather than the person conducting it and makes the report seem more objective.
However, some course areas accept the active form, particularly for a report written jointly with others—for example ‘We observed a colour change’).
Tense
When writing practical reports you sometimes use past tense and sometimes present tense.
Write in the past tense when you describe what you did in the practical:
The test tube was placed in a water bath at 30 ° C.
Use the present tense when you state generally accepted knowledge or generally true information:
Gravity exerts a force of 9.81 N/kg of mass.
Also write in the present tense when you refer to information contained in your report:
Figure 3 shows ...
Numbers
Follow these conventions which apply to the use of numbers:
- In general, one digit numbers are written in words, e.g. six. Larger numbers are written as numerals, e.g. 27.
- With standard units of measurement numerals are always used e.g. 3 mL.
- If values are smaller than one, insert a zero e.g. 0.25 not .25
- Use scientific or engineering notation for very large and very small numbers.
Number |
Scientific |
Engineering |
49100000 |
4.91 x 10 7 |
49.1 x 10 6 |
0.000025 |
2.5 x 10 -5 |
25 x 10 -6 |
Ensure you are working to an acceptable level of accuracy. For instance, 5, 5.0 and 5.00 indicate different degrees of precision.
Carefully distinguish between a zero result and no result. Zero results should be shown as ‘0’ and no results as ‘-’.
Units of measurement
When recording measured quantities, always use the appropriate SI (Systeme International) units in the correct format, eg. m 2 , µL, s. In a table, the unit of measurement is given in the column heading.
Scientific diagrams
Keep all diagrams clear, simple and accurate. Give each a complete title and perhaps an indication of scale. To name the parts of a diagram, draw a straight line to each part and label it. Make sure these lines do not cross each other.
For example
Sources
Eunson, B 1994, Writing and presenting reports, The Communication Series, John Wiley & Sons, Milton, Queensland.
Winckel, A & Hart, B 2002, Report writing style guide for engineering students, 4th edn, University of South Australia, Adelaide.