Course: Project Lead the Way Engineering Design and Development
Lesson 1 – Introduction to Design Concepts with Soda Bottle Rockets
Objective
It is all too common for design students to let the enthusiasm of the first idea-tomind overwhelm a rational consideration of the idea and comparison to alternative
solutions to the problem. This tunnel vision will often yield inefficient or costly
designs and the students will not develop an appreciation for the design process.
In this lesson, students will prepare themselves for the traditional yearlong EDD
project by completing an accelerated design project on soda bottle rockets. The
students will be introduced to all the design steps to be used for the main course while
working on a very narrow problem in large groups with guidance by the teacher and
GK-12 fellow. The design elements that will be new to the students are: the design
brief; the problem statement; the customer survey; prototype testing; and iterative
design. The design elements that may already be familiar to the students include:
brainstorming; data analysis; status reports and presentations; safety; and impact
analysis such as on energy and the environment.
This lesson is intended for high school seniors who have met the technologycourse unit requirement in their first three years. As a compact design project, many
STEM (Science, Technology, Engineering, and Math) subjects are employed for
successful completion of the unit - specifically: physics; aerospace engineering;
technical communication; and engineering statistics.
Key Concepts
1. The primary consideration in engineering design is the needs of the customer.
2. It is important to maintain an open mind when working towards a solution and
give all ideas from group members, brainstorming sessions, and project mentors
proper consideration even if these suggestions steer the prototype away from the
current design as long as customer needs continue to be met. In other words, there
is no intrinsic value or detriment to the project if the final solution resembles
initial ideas. In addition, all ideas are good ideas until the group decides otherwise
by thoughtful analysis.
3. Safety of the customer, engineers, and environment need to be top priority during
material selection and prototype testing.
4. A successful engineer must be able to communicate orally and in writing with
team members, the customer, and mentors. This is not limited to transmitting data,
but also sharing difficulties and the tools used to overcome them, meanwhile
being prepared to listen to feedback that may be helpful in future iterations of the
design.
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Course: Project Lead the Way Engineering Design and Development
Lesson 1 – Introduction to Design Concepts with Soda Bottle Rockets
Expectations
It is expected that students will:
•
Understand the definition and purpose of the “Design Brief” and “Problem
Statement” as engineering design tools and working documents.
•
Develop the professionalism to maintain focus on the needs of the customer
during the design process.
•
Apply the brainstorming, prototype testing, and design iteration experience to
the overall EDD course project.
•
Communicate design goals, testing data, and roadblocks concisely and
effectively with group members, customers, mentors, and the class at large.
Materials
Launcher (Construct separately – see: Launcher_Construction.pdf)
- Modified to launch rockets at an angle
Bicycle Pump with Pressure Gauge
Empty and Clean 2L Plastic Soda Bottles – 3-5 per group
Play-Doh
Foam Poster Board
Open Reel Measuring Tape (>300 ft)
Hot glue gun or tape
Water
Post-It notes
Computer with Microsoft Office, CAD Software
Key Terms
Customer Survey
Linear Regression
Interaction
Design Brief
Regression Model
Model Coefficient
Problem Statement
Model Estimate
Test Plan
Factor Effect
Engineering
Design
Opening Questions
1. What are three potential safety issues with this solution method in regards to the
users, the environment, or others? Propose a solution to each issue.
2. List five factors that unintentionally influenced our recent experimental
observations? Would you expect an identically prepared experiment to yield the
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Course: Project Lead the Way Engineering Design and Development
Lesson 1 – Introduction to Design Concepts with Soda Bottle Rockets
same results? How can an experimentalist reduce the influence of these noisy
factors in the data?
3. In your own words, define accuracy and precision. Additionally provide a point of
comparison and a point of contrast between these two concepts.
Lesson
Motivation
Train students to consider multiple design possibilities and find a basis to evaluate
them.
Provide a hands-on icebreaker with an outdoor activity.
Introduce the EDD design steps and vocabulary.
Time: 12 days – 80 minute periods
Day 1:
•
The teacher will introduce the lesson as an accelerated version of the overall
EDD project with an emphasis on learning the design vocabulary,
brainstorming and iterative design, and concise technical communication.
•
The teacher will present Handout 1: Customer Statement.
•
The students will watch NIGHTLINE: Deep Dive: 7/13/99 (~30 min)
•
The teacher will divide the class into large groups ~3 groups/class
•
In groups, the students will brainstorm with the post-its on a large flat area.
The students are encouraged to be very broad in solutions to the presented
problem. Around each solution idea presented, use more post-its to add
specific details, features, constraints, and considerations for each idea. (~20
min)
•
The teacher will move among the groups being sure to keep all group
discussion positive and supportive. At this point all ideas are valid.
•
The students will then refine the ideas generated by considering cost, safety,
energy, and the environment.
•
The students will need record the results of their brainstorming sessions in
their notebooks.
•
The students will produce a 5-7 question customer survey aimed at further
refining the brainstorming ideas based on the customer’s responses. The
survey should be structured in a way that the responses are given on a scale of
1 to 5. Questions should avoid being too leading, ambiguous, or confusing.
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Course: Project Lead the Way Engineering Design and Development
Lesson 1 – Introduction to Design Concepts with Soda Bottle Rockets
Day 2:
•
The teacher will introduce the “Problem Statement” from existing PLTW
materials.
•
The students, in groups, will write a Problem Statement
•
The teacher will introduce the bottle rocket as the solution to be pursued for
the remainder of the project.
•
The teacher will introduce the “Design Brief” from existing PLTW materials.
•
The students, as a whole class, will write a Design Brief.
•
Each group will launch an unmodified soda bottle rocket. Each group is to be
assigned a different amount of water to add to their rocket. They need to
record in their notebooks: amount of water added, internal air pressure, and
distance traveled. All launch angles should be 45° and launch pressures
should be 60 psi.
Day 3-4:
•
The teacher will distribute the Opening Questions and students will
individually answer the questions and record their answers in their notebooks.
•
The students are to share volume vs. distance data amongst the groups. Then,
in groups develop a mathematical relationship between the input and output.
Finally, from this relationship estimate the optimal water volume to travel the
distance required by the customer.
•
The teacher will explain the parametric constraints of the design to the
students. Namely, the only variables to be modified and tested are the volume
of water in the bottle, the aspect ratio of the wings, and the mass play-doh at
the nose.
•
The groups will update the design brief.
•
The students are to write a technical summary of their findings. This should be
no more than two pages long. It should include salient points from the design
activities to-date: problem identification; brainstorming; idea refinement
(decision matrix); problem statement; design brief, testing; and analysis. It is
appropriate for students to report questions they may have at this point in the
project and propose avenues to resolve them. The report should close with
reasoned guesses as to how adding fins and nose weight will affect
performance.
•
The groups will then prepare and deliver a Pecha Kucha-style presentation.
The presentation is to be 10 slides, automatically advancing at 20-second
intervals for a total length of 3 min 20 sec.
•
The teacher will guide the question and answer session after each presentation
as time allows.
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Course: Project Lead the Way Engineering Design and Development
Lesson 1 – Introduction to Design Concepts with Soda Bottle Rockets
Day 5-8:
•
The teacher will introduce the “Test Plan” from existing PLTW materials.
•
Each group will prepare a test plan
•
The students will continue testing prototypes, now free to vary all three
parameters: water volume; play-doh mass; and fin aspect ratio. A different fin
shape can be assigned to each group, for example – triangle, ellipse, and
rectangle. Final performance comparisons are made more meaningful if one
dimension is kept similar between the different shapes, such as the length of
the fin edge contacting the bottle always be 3.5 inches.
•
The teacher will distribute HANDOUT 2: Significance of Individual
Factors and Interaction and present the first half of Notes on Data
Collection and Analysis.
•
The students should perform low level data analysis and rate the relative
strengths of the three factors examined in their design.
•
The students should then update their test plan by incorporating Design of
Experiments ideas and continue testing.
Day 9:
•
The teacher should present the second half of Notes on Data Collection and
Analysis.
•
The students should perform multiple linear regression using MS Excel’s
LINEST function on five (5) models. They should analyze models with
various terms from their observations on the strength of the factors, factor
interactions, and other intuitions they have developed. They should record in
their notebooks their reasoning for each model they investigate along with the
least squares fit parameters and goodness of fit for each model.
•
The teacher needs to interact with groups during this step to keep students
from investigating very high order models. While very high order models may
fit experimental data better, the model terms lose physical meaning. It is to be
stressed that lower order, more physical models with a good fit to the data is
preferable to a very high order model with an “excellent” fit.
Day 10:
•
The students will use their best model to select factor values that predict a
flight outcome that best meets the customer needs. There will likely not be a
unique combination of factor values for a given model predicted distance. The
students should select two or three factor value sets for final testing.
•
The students will create a precision template of their final wing shapes with
CAD, print it to scale, and use it for constructing the wings of the final
prototype.
•
The students will perform their final flight tests.
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Course: Project Lead the Way Engineering Design and Development
Lesson 1 – Introduction to Design Concepts with Soda Bottle Rockets
Day 11-12:
•
The students will prepare and deliver a ten minute Power Point presentation of
their findings.
•
The students will write a 15 page final report.
The most important thing for the students to convey in these final
communication assignments is the evolution of the design and
design documents over the course of the project. The students
should be encouraged to demonstrate how they used
brainstorming, the design brief, and the test plan to iterate the
design as they gained more skills and intuition about parametric
design. It is also import to show how feedback from the first
presentation, discussions with teachers, and prototype testing was
incorporated into the design process. There also needs to a section
on outcomes, both in terms of data collected and models analyzed,
but also the ultimate goal of meeting the needs of the customer. It
is also good to indicate problems that arose and how they were
resolved, as well as issues that remain unresolved. Students are
encouraged to comment on the experience of having the design
variables tightly constrained, their hypotheses of the effects of
other possible variables, and suggesting for future redesigns to
improve compliance with customer needs.
Closing Questions
1. Estimate the maximum number of bottles that can be delivered in this manner, per
week, before it ceases to be a money saving endeavor. If you need to assume
values for any costs or fees in your calculation, please clearly state them in your
work.
2. What design factors were investigated in your solution? Please rank them by
strength of effect on the measured output.
3. What is the intent of the Design Brief? The Problem Statement? List two other
ways in which these design elements are different.
4. Name a specific occurrence from discussion or testing that modified the course of
the product design for you. Why did it do so?
5. Did your final design meet the customer’s needs? How many trials did you run
with the final design specifications? What percentage of those trials were within
specification? What is the minimum percentage of success for a marketable
solution? What considerations and trade-offs led you to this value?
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Course: Project Lead the Way Engineering Design and Development
Lesson 1 – Introduction to Design Concepts with Soda Bottle Rockets
Resources
Power Point Presentations
Notes on Data Collection and Analysis
- “Rocket Data Notes.ppt”
PDF Documents
Handout 1: Customer Statement
- “Customer Statement.pdf”
Handout 2: Significance of Individual Factors and Interaction
- “Exp_Factor_Analysis.pdf”
- Excerpts from Montgomergy, 2001 Reference
Handout 3: LINEST Excel function help file
- “linest_win.pdf”
Rockets_Rowan_University.pdf (Riddell et al., 2006 Reference)
Video Program
NIGHTLINE: Deep Dive: 7/13/99
- Available as VHS, DVD or online (see References)
References
Montgomery, D. C. Design and Analysis of Experiments. 5th Ed. Hoboken, NJ:
John Wiley & Sons, Inc., 2001.
NIGHTLINE: Deep Dive: 7/13/99
VHS or DVD: http://abcnewsstore.go.com/
Online: http://www.youtube.com/watch?v=z6z-3ejvvGE
Pecha Kucha on Wikipedia: http://en.wikipedia.org/wiki/Pecha_Kucha (accessed on
8-25-09)
Riddell, W., Constans, E., Courtney, J., Dahm, K., Harvey, R., Jansson, P., Simone,
M., and Von Lockette, P. “Lessons learned from teaching project based learning
communications and design courses.” Proceedings of the 2007 Middle Atlantic
Section Fall Conference of the American Society for Engineering Education.
Von Lockette, P., Acciani, D., Courtney, J., Diao, C., Riddell, W., Dahm, K.,
Harvey, R., “Bottle Rockets and Parametric Design in a Converging-Diverging
Design Strategy,” Proceedings of the 2006 Annual American Society for
Engineering Education Conference (2006-497), Chicago, IL, 2006.
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