Grade 5 · Low-Tech Builds · Lesson 100

Big-and-Small Sieve

Make a tabletop sieve that separates two sizes of large paper balls into a tray.

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

Your project in view

What you are making

Make a tabletop sieve that separates two sizes of large paper balls into a tray.

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 Big-and-Small Sieve: Make a tabletop sieve that separates two sizes of large paper balls into a tray.
Big-and-Small Sieve · Generated project example

Student directions · Grade 5

What will you make and do?

Make a tabletop sieve that separates two sizes of large paper balls into a tray.

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

    Measure both ball sizes and sketch an opening between those sizes. Keep all pieces too large for mouthing.

  2. 2Make the first parts

    Ask the teacher to cut the planned openings in the card. Fold a rim that holds the mixed balls inside.

  3. 3Put it together

    Support the sieve over a shallow tray so smaller balls can fall through freely.

  4. 4Test it fairly

    Use the same mixed set and five gentle side-to-side movements. Count correctly separated and incorrectly placed balls.

  5. 5Improve one part

    Change one opening size in a new sample or remove a catching edge. Repeat the same mixture and movements.

  6. 6Show and turn in

    Submit opening measurements and correct-out-of-total results with the sieve.

How will you know it works?

  • Separates the two sizes without hand sorting
  • Keeps balls contained in sieve or tray
  • 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 a tabletop sieve that separates two sizes of large paper balls into a tray. 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: Separates the two sizes without hand sorting; Keeps balls contained in sieve or tray.

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: Use the same mixed set and five gentle side-to-side movements. Count correctly separated and incorrectly placed balls. Change one opening size in a new sample or remove a catching edge. Repeat the same mixture and movements.

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

Materials

  • Cardboard with adult-cut openings
  • two sizes of large paper balls
  • tray
  • ruler
  • Pencil, planning paper and the printable design brief below

Teacher preparation

  1. Gather per-pair materials: Cardboard with adult-cut openings; two sizes of large paper balls; tray; ruler.
  2. Make one rough sample and rehearse the exact test: Use the same mixed set and five gentle side-to-side movements. Count correctly separated and incorrectly placed balls.
  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 a tabletop sieve that separates two sizes of large paper balls into a tray.
  2. Measure both ball sizes and sketch an opening between those sizes. Keep all pieces too large for mouthing.
  3. Students say what would count as a successful result.
Meeting 1 · 8–18 min

Model the unfamiliar action

  1. Demonstrate slowly: Ask the teacher to cut the planned openings in the card. Fold a rim that holds the mixed balls inside.
  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. Support the sieve over a shallow tray so smaller balls can fall through freely.
  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. Use the same mixed set and five gentle side-to-side movements. Count correctly separated and incorrectly placed balls.
  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 opening size in a new sample or remove a catching edge. Repeat the same mixture and movements.
  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 opening measurements and correct-out-of-total results with the sieve.
  2. Collect the brief and results; separate reusable materials and clean the test area.

Assessment

  • Separates the two sizes without hand sorting
  • Keeps balls contained in sieve or tray
  • Student demonstrates the actual task: Use the same mixed set and five gentle side-to-side movements. Count correctly separated and incorrectly placed balls.
  • 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 big-and-small sieve before decoration.
  • Extension after success: choose one more value for the same tested feature, predict its effect and repeat use the same mixed set and five gentle side-to-side movements.

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 a tabletop sieve that separates two sizes of large paper balls into a tray. If physical testing is not possible, label sketches as predictions rather than measured results.

Printable student design brief

The challenge

Make a tabletop sieve that separates two sizes of large paper balls into a tray.

Success criteria

  • Separates the two sizes without hand sorting
  • Keeps balls contained in sieve or tray
  • 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: Use the same mixed set and five gentle side-to-side movements. Count correctly separated and incorrectly placed balls.
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.
← Return to lesson library