Grade 3 · 3D Printing · Lesson 01

Design a Helpful Desk Tool

Notice a real classroom need, prototype a solution, and improve it with evidence.

Time2 × 60 minutes + adult printingTeamsTeams of 3–4EquipmentBambu P1S fleet

Project inspiration · 3 images

See, build, and test

Use these images to understand the kind of making, details, and testing involved. They are inspiration—not designs students must copy.

Desk tool project overview
01Project overview
Desk tools seen from a low front and side angle
02Front and side
Desk tools and planning sketch seen from above
03Top view

Student directions · Grade 3

What will you make and do?

You will make a small tool that fixes one desk problem, such as a pencil rolling away or a cable slipping off the edge. You will try a quick model before asking for a 3D print.

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

    Watch someone use the desk. Name one problem, measure the object your tool must fit, and draw two possible tool shapes with labels.

  2. 2Make the first parts

    Build your chosen shape from cardboard, clay or foam. Put the actual classroom object in it and check that the tool sits flat.

  3. 3Put it together

    Use your measurements to model the tested shape in the approved CAD tool. Ask the teacher to check thickness, size and print time before printing.

  4. 4Test it fairly

    Try the same desk task three times with the same object. Record whether the tool holds it, tips over or makes the task harder.

  5. 5Improve one part

    Change the opening, base or shape that caused the problem. Test the changed model before requesting another print.

  6. 6Show and turn in

    Show your tool in use. Turn in two labeled ideas, the important measurements, three test results and a before-and-after sketch.

How will you know it works?

  • Solves the chosen problem
  • Stays stable during use
  • Can be explained and tested

Before you move on

Tell a partner what you are making. Point to the part you will work on next. Draw or dictate your test notes if writing slows you down.

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

Teams define a desk-related need and identify success criteria plus size, material, and time constraints.

What students show: Completed problem frame and labeled design sketch.
Practiced

3-5-ETS1-2

Teams sketch two ideas and select one using a criteria-and-constraints check.

What students show: Two sketches and a written or spoken comparison.
Assessed

3-5-ETS1-3

Teams use the same three-part test before and after revising one feature.

What students show: Test record showing a result, revision, and retest.

Materials

  • Sticky notes and pencils
  • Rulers
  • Cardboard, index cards, tape, and modeling clay
  • Small classroom objects for testing
  • Shared tablet or computer with beginner 3D-design software
  • PLA filament; target 8–15 g per team

Teacher preparation

  1. Gather examples such as a pencil rest, cable guide, name-tag stand, or supply divider without presenting one as the required answer.
  2. Create team material trays and a 10 cm × 10 cm size-check card.
  3. Prepare a shared file folder and naming rule: G3_Team##_DeskTool_v1.
  4. Set a maximum print time of about 45 minutes per team and plan shared build plates across the 10 printers.

Step by step

How to teach it

0–10 min

Notice and define

  1. Students silently notice small desk frustrations.
  2. Teams choose one need and complete: ‘We need a way to…’
  3. Set criteria: what must the tool do? Set constraints: size, material, time, or cost.
10–25 min

Imagine and compare

  1. Each team makes two labeled sketches.
  2. Circle features that address each criterion.
  3. Use a simple plus/check/minus comparison to choose or combine ideas.
25–45 min

Build and test

  1. Build a cardboard or clay prototype.
  2. Write one repeatable three-step test.
  3. Run the test twice and record what happened without changing the test.
45–60 min

Improve and explain

  1. Change one feature based on evidence.
  2. Retest using the same procedure.
  3. Share: ‘Our evidence showed…, so we changed…’
Day 2

Move into 3D

  1. Measure the improved prototype.
  2. Create a small digital model using basic solids and holes.
  3. Teacher checks dimensions, stability, naming, and print time before adding it to the queue.
  4. After printing, teams compare the printed object with their prototype and record one next improvement.

Assessment

  • Problem includes a clear need, two criteria, and two constraints.
  • Sketches show two meaningfully different possibilities.
  • Test is repeatable and linked to a criterion.
  • Revision is supported by recorded evidence.

Supports & extensions

  • Provide picture cards of common desk needs.
  • Use sentence stems for the problem and evidence statements.
  • Allow drawing, speaking, or teacher scribing instead of extended writing.
  • Offer pre-cut cardboard shapes and adaptive scissors.
  • Extension: calculate footprint area and reduce material while keeping performance.

Safety & responsible use

  • Students do not touch hot ends, heated beds, or moving printer parts.
  • An adult handles slicing approval, printer setup, part removal, and sharp tools.
  • Use only lab-approved filament and supervised software accounts.

No-machine alternative

Use air-dry clay, cardboard, or reusable building pieces as the final product. Complete the same measurement, test, and revision cycle without printing.

Printable student design brief

The challenge

Design a small tool that makes a classroom desk easier, safer, or more organized to use.

Success criteria

  • Solves the chosen problem
  • Stays stable during use
  • Can be explained and tested

Constraints

  • Fits inside 10 cm × 10 cm × 10 cm
  • Uses one small print or a no-print prototype
  • Can be tested during class

Engineer’s notes

The problem we noticed is…
Our two ideas are different because…
Our test will show whether…
The evidence showed…
We improved our design by…
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