Grade 5 · Low-Tech Builds · Lesson 88

Fold a Strong Beam

Make three beam shapes from equal-size cards and compare which supports a small central load with the least bending.

Time2 × 45 minutesTeamsPairs; alternate builder and testerEquipmentBasic classroom materials; no powered equipment

Your project in view

What you are making

Make three beam shapes from equal-size cards and compare which supports a small central load with the least bending.

This generated example illustrates one possible finished design—not actual student work. Use the lesson’s sizes, connected parts and safety steps; your colors and creative details can be different.

Generated finished-project example for Fold a Strong Beam: Make three beam shapes from equal-size cards and compare which supports a small central load with the least bending.
Fold a Strong Beam · Generated project example

Student directions · Grade 5

What will you make and do?

Make three beam shapes from equal-size cards and compare which supports a small central load with the least bending.

Teacher overview: Students will plan the specific object described below, make and test a first version, then use their results to improve it. Read one step together, demonstrate the unfamiliar action, and let students complete that step before moving on.

  1. 1Plan your project

    Draw flat, channel and accordion cross-sections. Predict which will carry the teacher’s small target load.

  2. 2Make the first parts

    Fold one card into each chosen shape while keeping the same paper amount.

  3. 3Put it together

    Place each beam across the same support gap and mark the middle loading point.

  4. 4Test it fairly

    Add the same counters in the same order. Record the load and visible bending using an agreed stopping rule.

  5. 5Improve one part

    Change one fold depth in the chosen beam and repeat the same gap and loading sequence.

  6. 6Show and turn in

    Submit cross-sections, load records and a conclusion tied to the tests rather than appearance.

How will you know it works?

  • Uses equal card amounts for comparison
  • Supports the agreed load across the gap
  • Record the stated test and explain one revision

Before you move on

Explain which measurement, input or design choice you are testing. Predict the result and record what stays the same so your comparison is fair.

Machine cutting, printer setup and electrical power-on require adult approval. A basic-materials model is a valid way to demonstrate the design when equipment is unavailable.

Keep your plan, test notes and before-and-after evidence with the printable design brief below. Use the detailed teacher plan and any coding guide for tool instructions. These steps continue across the lesson’s meetings, not all in one sitting.

For teachers

Engineering standards

This shows how the lesson connects to the national NGSS engineering standards and what student work you can collect.

Assessed

3-5-ETS1-1

Define the need in Make three beam shapes from equal-size cards and compare which supports a small central load with the least bending. Agree on the two success checks and the listed material limits.

What students show: Two labeled ideas with the target and limits stated.
Practiced

3-5-ETS1-2

Compare the ideas using the project checks: Uses equal card amounts for comparison; Supports the agreed load across the gap.

What students show: A selected design with a reason connected to a success check.
Assessed

3-5-ETS1-3

Test, change one feature and retest: Add the same counters in the same order. Record the load and visible bending using an agreed stopping rule. Change one fold depth in the chosen beam and repeat the same gap and loading sequence.

What students show: Before-and-after results collected under the same conditions.

Materials

  • Equal index cards
  • two supports
  • large identical counters
  • ruler
  • Pencil, planning paper and the printable design brief below

Teacher preparation

  1. Gather per-pair materials: Equal index cards; two supports; large identical counters; ruler.
  2. Make one rough sample and rehearse the exact test: Add the same counters in the same order. Record the load and visible bending using an agreed stopping rule.
  3. Set the size, load or distance marks mentioned in the steps before class. Demonstrate an ordinary first attempt, not a perfect model to copy.
  4. Prepare any holes, fasteners or difficult cuts for students. Check the stated safety note and clear the testing space.

Step by step

How to teach it

Meeting 1 · 0–8 min

See the job and plan

  1. Introduce the finished object: Make three beam shapes from equal-size cards and compare which supports a small central load with the least bending.
  2. Draw flat, channel and accordion cross-sections. Predict which will carry the teacher’s small target load.
  3. Students say what would count as a successful result.
Meeting 1 · 8–18 min

Model the unfamiliar action

  1. Demonstrate slowly: Fold one card into each chosen shape while keeping the same paper amount.
  2. Pause so partners can repeat the action; provide prepared parts if cutting or folding blocks progress.
Meeting 1 · 18–35 min

Build the first version

  1. Place each beam across the same support gap and mark the middle loading point.
  2. Partners swap builder and checker roles halfway through. Check the working part before decorating.
Meeting 1 · 35–45 min

Try once and save

  1. Run one trial of the stated test to locate an obvious problem. Do not count a changed procedure as a fair comparison.
  2. Label and store the model; sketch its current shape and clear the work area.
Meeting 2 · 0–8 min

Predict and set up

  1. Revisit the two success checks. Agree on identical starting conditions and prepare a before/after results table.
Meeting 2 · 8–23 min

Collect evidence

  1. Add the same counters in the same order. Record the load and visible bending using an agreed stopping rule.
  2. One student operates while the other records. Swap for a later trial while noting a change of operator if it affects the result.
Meeting 2 · 23–35 min

Change one thing

  1. Change one fold depth in the chosen beam and repeat the same gap and loading sequence.
  2. Keep the original results rather than replacing them with only the best attempt.
Meeting 2 · 35–45 min

Explain and clean up

  1. Submit cross-sections, load records and a conclusion tied to the tests rather than appearance.
  2. Collect the brief and results; separate reusable materials and clean the test area.

Assessment

  • Uses equal card amounts for comparison
  • Supports the agreed load across the gap
  • Student demonstrates the actual task: Add the same counters in the same order. Record the load and visible bending using an agreed stopping rule.
  • Record includes failures as well as successes.
  • Student identifies one changed feature and uses the retest to explain the result.

Supports & extensions

  • Provide a worked first joint or sample; have students record dimensions and explain one comparison limitation.
  • Start with the smallest working version of fold a strong beam before decoration.
  • Extension after success: choose one more value for the same tested feature, predict its effect and repeat add the same counters in the same order.

Safety & responsible use

  • Teacher checks materials and test conditions before use. Use classroom scissors; adults prepare difficult cuts, holes and fasteners.
  • No powered tools, coding, hot glue or electrical circuits are required. Keep moving objects contained and test loads light.
  • Keep pieces on the tabletop, do not mouth materials and stop if a part tears into a sharp or loose hazard.

No-machine alternative

Use prepared paper parts, larger pieces or an adult-assisted version of the same build. Keep the functional task: Make three beam shapes from equal-size cards and compare which supports a small central load with the least bending. If physical testing is not possible, label sketches as predictions rather than measured results.

Printable student design brief

The challenge

Make three beam shapes from equal-size cards and compare which supports a small central load with the least bending.

Success criteria

  • Uses equal card amounts for comparison
  • Supports the agreed load across the gap
  • Record the stated test and explain one revision

Constraints

  • Use only the listed teacher-approved materials
  • Stay within the teacher-set size, load and test-space limits
  • Two 45-minute meetings; keep the first version simple

Engineer’s notes

Who uses this object, and what should it do?
Draw two possible designs. Label the working parts and circle your choice.
Which size, fold, gap or position must you measure or mark?
Before testing, predict what will happen: Add the same counters in the same order. Record the load and visible bending using an agreed stopping rule.
Record each trial: condition / expected result / actual result.
Draw the ONE change you made. What stayed the same?
Record the retest. Did the change help, not help, or leave the result uncertain?
Show and explain: one result that supports your conclusion.
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