2. Report Writing

• As engineers, reports are the most common form of document we will write.

• Report writing is an art that we often overlook, but in many cases can make a dramatic impact on our progression.

• Your reports are most likely to find their way to a superiors desk than you are to meet the individual.

• Note: typically these documents are done as a long written document -this is done in point form for more mercenary reasons.

2.1 Why Write Reports?

• Reports are written for a number of reasons,

- (lets forget about this one) as a student you must do them to get marks

- to let other engineers know the results of an experiment

- to leave a record of work done so that others may continue on

- as a record you may use yourself if you must do work again some time later

- they are required for legal reasons (contract or legislation)

- they bring closure to the project

2.2 The Technical Depth of the Report

• This is the most common question for beginning report writers.

• Always follow the doctrine: “What happens if I am hit by a car; could another pick up my report and continue?” if the answer to this question is no the report is too short.

• Always ask the question: “If I was reading this before starting the project would I look at this section and say it is not needed?”. If the question we are probably best to condense the section or leave it out.

• Avoid more artistic sections. If you put these in, make it clear that they are an optional part of the report and can be skipped. It is somewhat arrogant to force the reader to

2.3 Types of Reports

• We do different types of reports, including,

Laboratory: Theses ‘Lab Reports’ describe one or more experiments, the results, and the conclusions drawn from them.

Consulting: A summary of details, test results, observations, and a set of conclusions. Typically they will also contain a recommendation.

Project: A description of work done in a project to inform other engineers who may be asked to take up further work on the project.

Research: A summary of current advances in a topic. This should end with some comparison of alternatives.

Interim: A report to apprise supervisors and others as to the progress of a project or other major undertaking.

Executive: A brief summary of the report, and any implications for decision making at the management levels.

2.3.1 Laboratory

• Purpose: These reports should outline your procedure and results in detail. They should also contain the analysis and conclusions. The completeness of detail allows you (and others) to review these and verify the correctness of what has been done. These have been historically used for hundreds of years and are accepted as a form of scientific and legal evidence. It is completely unacceptable to make incorrect entries or leave out important steps or data.

• Standard Format:

1. Title, Author, Date: these make it clear what the labs contain, who did the work, and when it was done.

2. Purpose: a brief one line statement that allows a quick overview of what the experiment is about. This is best written in the form of a scientific goal using the scientific methods.

3. Theory: a review of applicable theory and calculations necessary. Any design work is done at this stage

4. Equipment: a list of the required equipment will help anybody trying to replicate the procedure. Specific identifying numbers should be listed when possible. If there are problems in the data, or an instrument is found to be out of calibration, we can track the problems to specific sets of data and equipment.

5. Procedure: these are sequential operations that describe what was done during the experiment. The level of detail should be enough that somebody else could replicate the procedure. We want to use this as a scientific protocol.

6. Results (Note: sometimes procedure and results are mixed): the results are recorded in tables, graphs, etc. as appropriate. It will also be very helpful to note other events that occur (e.g. power loss, high humidity, etc.)

7. Discussion: At this stage the results are reviewed for trends and other observations. At this point we want to consider the scientific method.

8. Conclusions: To conclude we will summarize the significant results, and make general statements either upholding or rejecting our purpose.

• Style: These are meant to be written AS the work is done. As a result the work should be past tense

• Laboratory reports should have one or more hypotheses that are to be tested. If testing designs these are the specifications. Examples might be,

what is the thermal capacity of a material?

what is the bandwidth of an amplifier?

will the counter increment/decrement between 0 to 9?

• NOTE: These reports are much easier to write if you prepare all of the calculations, graphs, etc. before you start to write. If you sit down and decide to do things as you write it will take twice as long and get you half the marks...... believe me, I have written many in the past and I mark them now. - An Example First Draft of a Report

Note: This is unformatted intentionally

Grand Valley State University

Padnos School of Engineering

EGR 345 Dynamics Systems Modeling and Control

Laboratory Exercise 7

Title: The Cooling of Coffee

Author: I. M. Wyred

Date: Dec., 23, 1998

Purpose: To derive a theoretical model of the rate at which coffee cools and experimentally verify the model and find coefficients.


When coffee is heated kinetic energy is added, when coffee is cooled kinetic energy is removed. In a typical use, coffee cools as heat is lost through convection and conduction to the air and solids in contact. The factors involved in this convection/conduction can be difficult to measure directly, but we can approximate them with a simple thermal resistance. Consider the temperature difference between the coffee and the ambient temperature. The greater the temperature difference, the higher the rate of heat flow out of the coffee. This relationship can be seen formally in the equation below. We can also assume that the atmosphere is so large that the heat transfer will not change the temperature.


We can also consider that coffee has a certain thermal capacity for the heat energy. As the amount of energy rises, there will be a corresponding temperature increase. This is known as the thermal capacitance, and this value is unique for every material. The basic relationships are given below. I will assume that the energy flow rate into the coffee is negligible.


The temperatures can be found by consider that the energy flowing out of the cup, and into the atmosphere is governed by the resistance. And, the temperature in the coffee and air are governed by the two capacitances. We will make two assumptions, that the thermal capacitance of the atmosphere is infinite, and that there is no energy flowing into the coffee.


This differential equation can then be solved to find the temperature as a function of time.


The time constant of this problem can be taken from the differential equation above.



1 ceramic coffee cup (14 oz.)

2 oz. ground coffee

1 coffee maker: Proctor Silex Model 1234A

1 thermocouple (gvsu #632357)

1 temperature meter (gvsu #234364)

1 thermometer

2 quarts of tap water

1 standard #2 coffee filter

1 clock with second hand

1 small scale (gvsu# 63424)


1. The coffee pot was filled with water and this was put into the coffee maker. The coffee filter and grounds were put into the machine, and the machine was turned on. After five minutes approximately the coffee was done, and the pot was full.

2. The mass of the empty coffee cup was measured on the scale and found to be 214g.

3. The air temperature in the room was measured with the thermometer and found to be 24C. The temperature of the coffee in the pot was measured using the thermocouple and temperature meter and found to be 70C.

4. Coffee was poured into the cup and, after allowing 1 minute for the temperature to equalize, the temperature was measured again. The temperature was 65C. Readings of the coffee temperature were taken every 10 minutes for the next 60 minutes. These values were recorded in Table 1 below. During this period the cup was left on a table top and allowed to cool in the ambient air temperature. During this period the mass of the full coffee cup was measured and found to be 478g.



The difference between the temperature of the coffee in the pot and in the cup was 5C. This indicates that some of the heat energy in the coffee was lost to heating the cup. This change is significant, but I will assume that the heating of the cup was complete within the first minute, and this will have no effect on the data collected afterwards.

The readings for temperature over time are graphed in Figure 1 below. These show the first order response as expected, and from these we can graphically estimate the time constant at approximately 32 minutes.


We can compare the theoretical and experimental models by using plotting both on the same graph. The graph clearly shows that there is good agreement between the two curves, except for the point at 30 minutes, where there is a difference of 3.5 degrees C.


This gives an overall error of 8.5% between these two curves, compared to the total range of the data.


Finally, the results can be used to calculate a thermal resistance. If we know the mass of the coffee and assume that the coffee has the same specific heat as water, and have the time constant, the thermal resistance is found to be 1731sC/J.



In general the models agreed well, except for a single data point. This error was relatively small, only being 8.5% of the entire data range. This error was most likely caused by a single measurement error. The error value is greater than the theoretical value, which suggests that the temperature might have been read at a "hot spot". In the procedure the temperature measuring location was not fixed, which probably resulted in a variation in measurement location.

2.3.2 Research

• Purpose: After looking at a technical field we use these reports to condense the important details and differences. After reading a research report another reader should be able to discuss advanced topics in general terms.

• Strategy A:

1. Clearly define the objectives for the report

2. Outline what you know on a word processor in point form and find the ‘holes’

3. Do research to find the missing information

4. Incorporate the new and old information (still in point form)

5. Rearrange the points into a logical structure

6. Convert point form into full text

7. Proof read and edit

2.3.3 Project

• Purpose: These reports allow the developer or team to document all of the design decisions made during the course of the project. This report should also mention avenues not taken. Quite often the projects that we start will be handed off to others after a period of time. In many cases they will not have the opportunity to talk to us, or we may not have the time. These reports serve as a well known, central document that gathers all relevant information.

• Strategy A:

1. Define the goals for the project clearly in point form

2. Examine available options and also add these in point form

3. Start to examine engineering aspects of the options

4. Make engineering decisions, and add point form to the document

5. As work continues on the project add notes and figures

6. When the project is complete, convert the point form to full text.

7. Proof read and edit

2.3.4 Executive

• Purpose: These reports condense long topics into a very brief document, typically less than one page in length. Basically these save a manager from having to read a complete report to find the details that interest him/her.

2.3.5 Consulting

• Purpose: These reports are typically commissioned by an independent third party to review a difficult problem. The consultant will review the details of the problem, do tests as required, and summarize the results. The report typically ends with conclusions, suggestions or recommendations.

2.3.6 Interim

• Purpose: This report is normally a formal report to track the progress of a project. When a project is initially planned, it will be given a timeline to follow. The interim report will indicate progress relative to the initial timeline, as well as major achievements and problems.

2.4 Elements of Reports

• In reports we must back up our opinions with data, equations, drawings, etc. As a result we use a number of common items,




• When these elements are included, there MUST be a mention of them in the written text.

• These days it is common to cut and paste figures in software. Make sure

the resolution is appropriate

the colors print properly in the final form or print well as black and white

the smallest features are visible

scanned drawings are clean and cropped to size

scanned photographs are clear and cropped to size

digital photographs should be properly lit, and cropped to size

screen captures are clipped to include only relevant data

2.4.1 Figures

• Figures include drawings, schematics, graphs, charts, etc.

• They should be labeled underneath sequentially and given a brief title to distinguish it from other graphs. For example “Figure 1: Voltage and currents for 50 ohm resistor”

• In the body of the report the reference may be shortened to ‘Fig. 1’

• The figures do not need to immediately follow the reference, but they should be kept in sequence. We will often move figures to make the type setting work out better.

• If drawing graphs by computer,

if fitting a line/curve to the points indicate the method used (e.g. linear regression)

try not to use more than 5 curves on the same graph

use legends that can be seen in black and white

clearly label units and scales

label axes with descriptive term. For example “Hardness (RHC)” instead of “RHC”

scale the curve to make good use of the graph

avoid overly busy graphs


2.4.2 Tables

• Tables are often treated as figures.

• They allow dense information presentation, typically numerical in nature.


Table 1: A Comparison of Toy Vehicle Properties










die cast











• Legends can be added to tables to help condense size.

2.4.3 Equations

• When presenting equations, use a good equation editor, and watch to make sure subscripts, etc are visible.

• Number equations that are referred to in the text.

• Box in equations of great significance.


2.4.4 Experimental Data

• When analyzing the results from an experiment there are a few basic methods that may be used,

Percent difference:

Mean and standard deviation -

Point by point:

Matching functions:


2.4.5 References

• References help provide direction to the sources of information when the information may be questioned, or the reader may want to get additional detail.

• Reference formats vary between publication sources. But, the best rule is be consistent.

• One popular method for references is to number them. The numbers are used in the body of the paper (eg, [14]), and the references are listed numerically at the end.

• Another method is to list the author name and year (eg, [Yackish, 1997]) and then list the references at the end of the report.

• Footnotes are not commonly used in engineering works.

2.4.6 Acknowledgments

• When others have contributed to the work but are not listed as authors we may choose to recognize them.

• Acknowledgments are brief statements that indicate who has contributed to a work.

2.4.7 Appendices

• When we have information that is needed to support a report, but is too bulky to include, one option is to add an appendix.

• Examples of appendices include,

reviews of basic theory

sample calculations

long tables of materials data

program listings

long test results

2.5 General Formatting

• Some general formatting items are,

number all pages sequentially, roman numerals starting from ‘i)’ on the first page arabic numerals starting from ‘1’ on the

or, number pages by section. This is very useful for multi part manuals for example ‘4-7’ would be the 7th page in the 4th section

if pages are blank label them ‘this page left blank’

number sections sequentially with roman or Arabic numerals

• For numbers,

use engineering notation (move exponents 3 places) so that units are always micro, milli, kilo, mega, giga, etc.

use significant figures to round the numbers

units are required always

• General English usage,

check spelling: note that you must read to double guess the smell checker.

check grammar

avoid informal phrases (e.g. “show me the money”)

define acronyms and jargon the first time you use them (e.g., IBM means “Ion Beam Manufacturing”)

• General style rules,

keep it simple (especially the introduction): most authors trying to be eloquent end up sounding long winded and pretentious. For example, “Electronic computer based digital readings can provided a highly accurate data source to improve the quality of the ascertained data.” could be replaced with “Computer based data collection is more accurate.”

get to the point and be concise. For example, “Readings of the pressure, as the probe was ascending up the chimney towards the top, were taken.” is better put “Pressure probe readings were taken as the probe was inserted”.

it is fine to say ‘I’ or ‘we’, but don’t get carried away.

don’t be afraid to reuse terms, phases or words if it is an exact description. For example, we could increase confusion by also describing translation as motion, movement, sliding, displacing, etc.

• General engineering rules are,

all statements should be justified, avoid personal opinions or ‘gut feels’

use exact engineering terms when needed, don’t try to get creative.