CAES1507 Professional and
Technical Written
Communication for
Engineers
Session Six
Theory and Design
Feedback on Introduction
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The background has to be adequate to justify the
prototype invention
Be sure the information about the request for the
project is correct
Pay attention to the use of tenses
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Background – Present and/or present perfect tense
Purpose of the project – Past tense
Purpose of the report – Present tense
Avoid using personal pronouns and
possessive adjectives such as “I” and “our”
Feedback on Introduction
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Use formal tone
Bear in mind that you’re asked to design and build a
prototype of the toy to be considered for mass
production, NOT the toy itself yet
Stick to the requirement of the project and what
you’re really going to cover in the report
Theory
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Other engineers need to know WHY you have done
what you have done in your design so that they can
duplicate it or improve it or change it in some way
Include formulae if necessary but you must explain
why you have included them.
Use theoretical principles to explain why you have
made the choices you have in your first design
and why you made the changes you did in your
second design.
Theory
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PRESENT TENSE should be used
unless you refer specifically to your
project, for which PAST TENSE is
used
You should include graphic
information.
Example –
What information is included?
The simple law of gravity
maintains the mousetrap in a
state of rest until a mouse
enters the system introducing
an
external
force
that
activates it. When the mouse
enters the trap, it creates a
force on the system due to its
weight. The force puts tension
on the wire activating the
other parts connected to it.
See Figure 1.
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A general
description of the
overarching
theory used
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Explanation of
theory
with specific
reference
to the prototype
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Refer to diagram
Example –
What information is included?
The fixed pulley in the prototype
mousetrap is used to change the
direction of tension in the strings.
The pulley is used so that the
tension of the string can be
transferred from one part to
another even if the string is bent or
twisted.
A prototype also uses a simple lever
system requiring a pivot point as
shown in Figure 1.
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Explanation of
functions of
specific parts
using
Engineering
principles
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Other relevant
engineering
principle
Critical Thinking

How would you propose to IMPROVE
the example in the booklet?
Writing Tips
1. Identify the theory/mechanism involved in
the design
2. Include equations/mathematic formulae if
necessary
3. Give examples to illustrate how the theory
is being applied in your design
4. Include diagrams or any other forms of
graphic information which aids explanation
+ Label the main parts of a diagram
Questions to be answered in
the Theory sections
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What theory or theories have you used in
your prototype design?
How is the respective theory used in a
component of your prototype?
Does the use of a mathematical/physics
equation help in explaining the mechanism
of a component of your prototype? If so,
how?
In-Class Practice Task –
How do Roller-Coasters Work?
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Work in groups, write the
theoretical principles
behind the operations of
roller-coasters. Your work
should include sketches of
diagrams and relevant
equations.
Design
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Identification of the major parts of
your prototype
Insert graphics (overall design +
different parts)
Describe the structure - major parts
(no need to include the procedures of
making them, which is in fact the focus
of next session)
Describing the major parts
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Provide a name of the part being described
Identify the major function of the part
Describe the function of each smaller
component
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Name of the
major part
General
Provide the specifications (e.g. The light bulb
will glow when activated indicating a mouse is
trapped)
Function of the
major part
Function of
smaller parts
Specifications
of smaller parts
Specific
Points to Note - Language
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Present Tense should be used
Signposting is needed to signal the structure
of your Design
Orientation –
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The bottom of…
On the right hand side of …
On top of…
Kitty corner to…
At the top right corner of…
Points to Note - Language
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Quantity –
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Two plastic wires…
Three wooden boxes …
Reference pronouns –
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This / it (make sure the readers know
what ‘it’ refers to)
Points to Note –
Graphical Representations
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Include diagrams (and must be
referred to in your text, e.g. Figure 1,
as shown in Figure 4)
Include a caption for each diagram
(e.g. Overall design of the burglar
alarm)
Label all important parts
An Example
The overall design of the
mousetrap (figure 1) can be
divided into three main parts,
the base, the light box and the
side track. The following
sections illustrate the overall
and completed design including
the structure and function of
each part.
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General
Introduction of the
design – the
components of the
prototype
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Signposting – i.e
what will be
included in the
following sections
An Example
The base in the main
body of mousetrap. This
is where the mouse
enters and is trapped.
The bottom of the base is
a movable platform
which is used to activate
the whole system.
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Introduction of the
component part
An Example
On the two side walls, there is a
wooden stick settled in a track on
each side and connected to the
platform by plastic string. The
wooden sticks are used to lock
and unlock the gate in front. The
gate is a sliding section which
covers one side of the base. When
it is released it slides down to
enclose the mouse completely in
the box. On the left hand side
wall, a little box which has an
inclined bottom and a hole on one
side is attached.
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Fairly general
description of the
structure and
mechanism
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Information:
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Structure of the
part
Function of the
part
An Example
This box is used to trap a marble
and the marble is trapped by
another wooden stick which is also
connected to the platform by wire.
Two plastic wires are connected to
the platform and then to the light
box. The structure of the base and
the inner mechanism of the base
are shown in Figures 2 and 3.
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Always refer to
relevant
diagrams
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Present Tense is
used
Comparison – Which
description is better?
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Read the other version of the
discussion of the Light Box design on
page 31. Compare this version with the
original on the same page. Which one
do you think is better? Why?
(Hint: think about the logical development)
Version one
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Function of the box
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How it works
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Size of the box
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Mechanism
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Refer to figures
Version Two
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Refer to figure 4
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Size of the box
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Function of the light box
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How it works
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Refer to figure 5
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Mechanism
General
Specific
The Side Track
1.
2.
3.
4.
5.
6.
7.
consists of
used
are activated
is released
rolls and falls
to make contact
show
Is made up of +
people/materials
Is made of + materials
Is made by + people
Homework
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Write the Theory section in group outside class. Hand in the
hardcopy to the class teacher in the next lesson.
Start building the prototype for demonstration in Session 8.
Start drafting the Design section in group outside class. You
will be required to hand it in Session 8.
Secretaries of the second meeting need to hand in the minutes
(in hard copy) in the next lesson. Make copies of your minutes
for your group members.