Grade 3 · Low-Tech Builds · Lesson 82

Model Rain Roof

Make a small sloping roof that guides a measured spoonful of water into a catch tray instead of onto a paper house floor.

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

Your project in view

What you are making

Make a small sloping roof that guides a measured spoonful of water into a catch tray instead of onto a paper house floor.

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 Model Rain Roof: Make a small sloping roof that guides a measured spoonful of water into a catch tray instead of onto a paper house floor.
Model Rain Roof · Generated project example

Student directions · Grade 3

What will you make and do?

Make a small sloping roof that guides a measured spoonful of water into a catch tray instead of onto a paper house floor.

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

    Sketch two roof slopes and draw arrows showing where water should go.

  2. 2Make the first parts

    Fold the coated paper into a pitched or single-slope roof and support it on the cardboard frame.

  3. 3Put it together

    Add a small folded gutter or extended edge above the catch tray. Keep the model inside a larger spill tray.

  4. 4Test it fairly

    Pour one teacher-measured spoonful at the same roof spot three times. Record where the water goes and whether the floor gets wet.

  5. 5Improve one part

    Change one roof slope or edge fold and repeat the same amount and pour position.

  6. 6Show and turn in

    Submit a water-path drawing and test notes with the roof model.

How will you know it works?

  • Guides water toward the catch tray
  • Keeps the model floor mostly dry under the agreed test
  • Record the stated test and explain one revision

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

Define the need in Make a small sloping roof that guides a measured spoonful of water into a catch tray instead of onto a paper house floor. 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: Guides water toward the catch tray; Keeps the model floor mostly dry under the agreed test.

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: Pour one teacher-measured spoonful at the same roof spot three times. Record where the water goes and whether the floor gets wet. Change one roof slope or edge fold and repeat the same amount and pour position.

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

Materials

  • Cardboard house frame
  • approved coated paper
  • tray
  • spoon
  • paper floor
  • towel
  • Pencil, planning paper and the printable design brief below

Teacher preparation

  1. Gather per-pair materials: Cardboard house frame; approved coated paper; tray; spoon; paper floor; towel.
  2. Make one rough sample and rehearse the exact test: Pour one teacher-measured spoonful at the same roof spot three times. Record where the water goes and whether the floor gets wet.
  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 small sloping roof that guides a measured spoonful of water into a catch tray instead of onto a paper house floor.
  2. Sketch two roof slopes and draw arrows showing where water should go.
  3. Students say what would count as a successful result.
Meeting 1 · 8–18 min

Model the unfamiliar action

  1. Demonstrate slowly: Fold the coated paper into a pitched or single-slope roof and support it on the cardboard frame.
  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. Add a small folded gutter or extended edge above the catch tray. Keep the model inside a larger spill tray.
  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. Pour one teacher-measured spoonful at the same roof spot three times. Record where the water goes and whether the floor gets wet.
  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 roof slope or edge fold and repeat the same amount and pour position.
  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 a water-path drawing and test notes with the roof model.
  2. Collect the brief and results; separate reusable materials and clean the test area.

Assessment

  • Guides water toward the catch tray
  • Keeps the model floor mostly dry under the agreed test
  • Student demonstrates the actual task: Pour one teacher-measured spoonful at the same roof spot three times. Record where the water goes and whether the floor gets wet.
  • Record includes failures as well as successes.
  • Student identifies one changed feature and uses the retest to explain the result.

Supports & extensions

  • Provide fold marks or pre-cut parts; accept drawings or dictated observations.
  • Start with the smallest working version of model rain roof before decoration.
  • Extension after success: choose one more value for the same tested feature, predict its effect and repeat pour one teacher-measured spoonful at the same roof spot three times.

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.
  • Shallow tray only, away from electronics. Wipe spills and wash hands after the activity.

No-machine alternative

Use prepared paper parts, larger pieces or an adult-assisted version of the same build. Keep the functional task: Make a small sloping roof that guides a measured spoonful of water into a catch tray instead of onto a paper house floor. If physical testing is not possible, label sketches as predictions rather than measured results.

Printable student design brief

The challenge

Make a small sloping roof that guides a measured spoonful of water into a catch tray instead of onto a paper house floor.

Success criteria

  • Guides water toward the catch tray
  • Keeps the model floor mostly dry under the agreed test
  • 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: Pour one teacher-measured spoonful at the same roof spot three times. Record where the water goes and whether the floor gets wet.
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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