Presentation format
One team deck prepared in Google Slides, PowerPoint or equivalent. Use approximately 8–10 focused content slides (the outline below suggests ten). Embed real photos, Fusion screenshots and at least one readable test graph.
Principles of Engineering • Unit 2 • Lesson 2.20
Bridge Design & Testing Presentation
Engineering question: How can we convince an audience—using real design evidence and honest measurements—that we understand why our bridge performed the way it did?
01 / Presentation assignment
Your final deliverable is a presentation to the class
Summarize the entire design–build–test process using evidence from Lessons 2.15–2.19. Your audience should understand what you designed, why you designed it, what you actually made, how it was tested, and what the results mean.
Time and participation
6–8 minutes speaking plus 2–3 minutes Q&A. Every team member speaks and should be prepared to answer an engineering question. Assign slide owners, rehearse handoffs and check that the class can read your graph.
Grading principle
A bridge that failed can earn full presentation credit if its measurements, engineering reasoning and lessons learned are accurate and well communicated. Missing or invented results must never be presented as successes.
Suggested preparation schedule: 1 period to assemble the deck and organize evidence, 1 period to refine figures and rehearse, and class presentation time as scheduled. Finished slides are submitted before speaking as directed by the teacher.
02 / What to include
Five things the audience must learn
Bridge design decisions
Compare the three concepts, identify the final truss design, show the Fusion assembly, and name the engineering trade-offs that drove the choice.
Predictions before testing
Include at least one real free-body/member-force calculation or risk assessment from 2.16. Label theoretical assumptions and predicted weaknesses.
Fabrication decisions
Show actual photos and approved materials/joints. Report final measured mass and one fabrication issue, modification or quality check.
Real experimental results
Present the actual 2.19 force–deflection graph, 100 N / 10 mm target, maximum observed load, actual test condition and numerical qualification evidence.
Engineering conclusion
Explain what matched or differed from analysis, identify the likely failure/deflection mechanism and propose two justified design improvements—without rebuilding the bridge.
Sources and credit
Credit externally sourced research visuals/information and identify your own CAD, measurements and team photographs. The class should be able to distinguish actual evidence from illustrative examples.
If your bridge never reached 100 N: Show the highest observed force and the actual reason the run stopped. State that the at-100-N requirement is unverified rather than inventing a value. If your bridge did not fail, do not claim an ultimate failure load.
03 / Slide planning studio
Recommended ten-slide presentation
Each slide below describes the required content, a visual example and a question to answer aloud. You may combine closely related slides, but all required topics must still be represented. The speaker and readiness fields help plan your group; they do not save automatically when you leave this browser page.
Our bridge in one sentence
Required content: Team name, selected truss type, and one-sentence design claim. Preview whether the actual bridge qualified; do not hide failures.
Suggested visual: Final bridge photo + team names
Speaker prompt
What did we build, and what is the headline finding?
The engineering challenge
Required content: State the required clear span 400 mm, width ≤65 mm, mass ≤150 g, centered 100 N and deflection ≤10 mm at 100 N. Mention approved manufacturing restrictions.
Suggested visual: Diagram of 400 mm span, 100 N center load, 10 mm limit
Speaker prompt
What did success require, and why is this hard?
Three concepts → one choice
Required content: Show three structurally different concepts and explain why the chosen one was selected using two specific engineering trade-offs.
Suggested visual: 2.15 side-view comparison + selection matrix
Speaker prompt
Why did our team choose this layout?
Our CAD model & load path
Required content: Identify two side trusses, span, actual overall width, center loading crossmember, lateral bracing and two important connections.
Suggested visual: Labeled Fusion assembly with side/top/isometric views
Speaker prompt
How does the force travel through this bridge?
Engineering predictions
Required content: Show support reaction calculations, at least one analyzed tension or compression member, and an anticipated failure risk or modeling uncertainty from 2.16.
Suggested visual: Annotated FBD and member-force or risk diagram
Speaker prompt
What did mechanics predict before fabrication?
Making the real bridge
Required content: Describe wood/plywood choices, joining method, actual final mass, fabrication process and one problem/decision from the build log.
Suggested visual: 2–3 labeled fabrication photos + short BOM
Speaker prompt
What did we have to change between CAD and reality?
How we tested it
Required content: Identify 400 mm supports, 100 N centered loading position, digital force gauge, fixed-datum deflection method, and official test stop conditions.
Suggested visual: Actual approved test setup photo with arrows
Speaker prompt
How do we know the data are valid and comparable?
Test results & qualification
Required content: Show actual readings and the 100 N / 10 mm markers, actual deflection at 100 N if recorded, highest observed force, whether the bridge met the numerical and material limits, and at least one correct N/g ratio.
Suggested visual: Actual labeled force–deflection graph + results table
Speaker prompt
Did the bridge qualify? Exactly what observations support that conclusion?
What worked, what failed
Required content: Compare at least one prediction against actual behavior. Explain deformation/failure mode and uncertainty. If no failure occurred, describe the highest demonstrated load and what was not determined.
Suggested visual: Test photo with labeled weakness and prediction comparison
Speaker prompt
Where did theory match reality—and where did it not?
Next iteration & conclusion
Required content: Recommend two specific changes connected to measured evidence. Describe expected improvement and trade-off. End with an evidence-based conclusion and invite questions.
Suggested visual: Annotated proposed revision sketch + 2 takeaways
Speaker prompt
What would we change next time, and what did our test teach us?
0 / 10Slides marked ready
0 / 10Slide owners assigned
—Suggested speaking time covered by ready slides
Select the slides you have completed and assign speakers.
04 / Examples of strong engineering visuals
Show the audience the evidence, not paragraphs about it
Illustration only: The graph above and its geometry are placeholders, not data from your bridge. You must replace them with the actual 2.19 graph, properly labeled axes (N and mm), and actual masses and force readings. In particular, show the 100 N / 10 mm requirement even if you did not achieve it.
Effective design slide
Use one large Fusion assembly screenshot with colored arrows or callouts for the center load, compression or tension forces, support reactions, and lateral bracing. Put dimensions on the image, not inside a dense paragraph.
Presentation sentence: “We selected this layout because ___, but our analysis predicted ___ could be vulnerable.”
Effective results slide
Use the real force–deflection graph alongside a short qualification table. Discuss the result verbally. Add a damage photo where helpful and identify what was observed versus predicted.
Presentation sentence: “At ___ N, the midpoint moved ___ mm; the requirement was ___, so our conclusion is ___.”
05 / Rehearsal and class Q&A
Prepare to explain the engineering rather than read slides
How to Avoid Death by PowerPoint — David JP Phillips, TEDx
Watch for: one main idea per slide, simple visuals and contrast that guides attention. Your engineering evidence still needs legible axes, quantities, and units.
Watch on YouTube ↗Practical rehearsal checklist
- Time the entire talk aloud; target 6–8 minutes total, not 6–8 minutes per student.
- Everyone has a meaningful speaking part and knows when to hand off.
- Slides use readable labels and contrast visible from the back of the classroom.
- Units appear on every graph axis and every engineering result.
- Each statement of “pass,” “failure,” “max load,” or “predicted” is supported by its correct evidence.
- Each team member can explain one design decision, one real measurement, and one likely failure mechanism.
- Practice responding to a question without reading the slide word for word.
PowerPoint Speaker Coach ↗ (optional tool for oral presentation feedback).
Questions classmates may ask
1. Why did you choose a Pratt/Warren/Howe layout?
Answer guidance
Reference the 2.15 decision matrix and a structural trade-off such as compression-member buckling risk, achievable joints or expected mass.
2. How did your 2.16 calculations compare with the test?
Answer guidance
State a predicted force or risk, cite actual observed behavior, and explain which assumptions of the model were too simple.
3. Did your bridge actually meet every requirement?
Answer guidance
Show measured span, width, mass, and a real 100 N / deflection pair if reached; distinguish an inconclusive test from a failed numerical result.
4. What load did the bridge really withstand?
Answer guidance
Report the highest demonstrated measured force. Do not call it ultimate strength unless failure was observed and its load established.
5. What would you change without adding too much mass?
Answer guidance
Identify the most consequential failure/deflection mechanism, a feasible change using permitted material/joints, and its expected drawback.
6. What measurement would you improve next time?
Answer guidance
Mention an uncertainty in fixture alignment, force-gauge calibration, fixed midspan reference, load step resolution, or mass measurement.
06 / Grading expectations
Presentation rubric — 100 points
Engineering evidence is weighted more heavily than polished decoration. The rubric evaluates the presentation students deliver, not whether the physical bridge passed. The score calculator is an optional teacher-scoring aid, and fields begin blank.
| Assessment criterion | Possible | Earned |
|---|---|---|
| Challenge, concepts and selection Accurate requirements; three concept alternatives; defensible structural choice. | 15 | |
| CAD design and engineering analysis Clearly labeled final bridge, load path, dimensions, forces and anticipated risks. | 15 | |
| Fabrication and technical accuracy True build documentation, material/joint choices, actual mass and revisions. | 10 | |
| Measured testing evidence Actual test setup, readable labeled graph, force/deflection, precise 100 N evidence (or honestly unverified), qualification and units. | 25 | |
| Interpretation and proposed improvement Prediction compared with observations; failure/risk analysis; two evidence-based improvements. | 15 | |
| Visual organization and citations Legible photos/CAD/data, focused slides, figure labels, consistent design and source credits. | 10 | |
| Oral delivery, timing, teamwork and Q&A 6–8-minute clear spoken presentation, meaningful contributions by all members, and evidence-based answers to classmates. | 10 | |
| TOTAL | 100 | — |
No rubric scores entered. Teacher enters earned points per category during or after the presentation.
How scores are determined: Full credit means all required evidence is accurate, legible and clearly explained. Partial credit reflects incomplete, unclear or unsupported evidence; omitted/invented engineering evidence cannot receive full credit. Individual participation may be considered within the teamwork category.
07 / Exact deliverables
What to submit and what to do in class
Submit before your scheduled presentation
- One team Google Slides link or editable PowerPoint presentation (as assigned).
- A PDF export of the same slides so the presentation can be graded even if links or media fail.
- Actual team CAD screenshots, dimensioned bridge photo(s), fabrication images and labeled load–deflection graph integrated into the deck.
- At least one engineering analysis visual from 2.16 and a correct, clearly labeled results/qualification table from 2.19.
- Two proposed redesign recommendations grounded in observed evidence—not a new physical build.
- Source credits on visuals or a final references area/slide.
Present to your classmates
- Speak for approximately 6–8 minutes per team.
- Every member explains a meaningful portion of the engineering process.
- Lead the audience through the bridge challenge, design, analysis, manufacture, test and results.
- Show the real graph and state which qualification criteria were met, failed or unverified.
- Answer classmates' questions for approximately 2–3 minutes.
- Be prepared to explain limitations honestly, including incomplete or unsuccessful tests.
Due date and presentation order: Check the Daily Agenda and teacher announcement.
No second build or retest is required for Lesson 2.20. Proposed improvements are presented as drawings, annotations, or engineering explanations. Your original bridge test data remain unchanged.