Scratch · Grade 3 · Guided practice
How to code this project
What you will make: Make a screen model of three shade positions before testing the cardboard shade.
Optional keyboard model, not an automatic sun sensor or a servo controller. Use the actual cardboard shade and lamp to decide which positions protect the target.
Before you start
- Paint a long horizontal shade sprite. Set rotation style to all around.
- Make a paper chart with columns key, screen direction, cardboard position and shaded area.
Opening and saving: Open the teacher-approved Scratch editor and select your sprite. The recipe is a block-by-block guide, not text to paste into Scratch. Build blocks with matching names and keep indented lines inside their enclosing blocks. Save through File → Save to your computer as an .sb3 file; no public sharing is required.
Build it one step at a time
- On the shade sprite, add the four separate scripts below. Events holds each key-pressed hat; Motion holds point in direction.
- Start with the green flag; then press 1, 2 and 3 one at a time.
- Sketch the three screen positions. In Scratch, direction 90 is right; these numbers are not servo angles.
- At each approved lamp position, manually adjust the real shade and record which position works best.
- Choose new screen directions to illustrate your observations. Explain that the keyboard stands in for a person choosing a position.
Your block recipe
when green flag clicked
point in direction (90)
when [1] key pressed
point in direction (60)
when [2] key pressed
point in direction (90)
when [3] key pressed
point in direction (120)Predict, test and record
Write your name and date on the printed page. Run every test, note the actual result, and retest after one change.
| Try this input | Expected result | Actual result / retest |
|---|---|---|
| Green flag | Returns to horizontal starting drawing | ________________ |
| Keys 1, 2, 3 | Three distinct rotations | ________________ |
| Repeat key 2 | Returns to the same position | ________________ |
If it does not work
- Does not rotate? Choose all-around rotation, not left-right.
- Image spins around an odd point? Check the costume center in the costume editor.
Make one change
Choose three positions that better represent your tested shade; label them in the chart.
We changed __________. We predicted __________. Our test showed __________.
Teacher pacing: Use a 45-minute coding session: 5 minutes to predict, 10 to model a first working response, 20 for paired building, 7 for tests and 3 to save and explain. Continue in another meeting if setup or debugging takes longer; do not rush hardware checks.
Grade 3 support: Model one block at a time; partners alternate choosing blocks and explaining the result. Accept spoken or drawn test evidence.
Teacher learning resources
Preview resources before class. Follow this page’s specified reference build; another tutorial may use different hardware.
Print support: The lesson’s Print button includes this guide, recipe and test table.
For teachers
Engineering standards
This shows how the lesson connects to the national NGSS engineering standards and what student work you can collect.
3-5-ETS1-1
Teams define who needs the solar shade tracker and set measurable performance, safety, material, and time limits.
What students show: User-centered problem statement with criteria and constraints.3-5-ETS1-2
Teams compare at least two circuit, code, or enclosure ideas against the success criteria.
What students show: Labeled system diagrams and a recorded design choice.3-5-ETS1-3
Teams run a repeatable test—move one lamp to three marked positions while keeping distance fixed—then change one variable and retest.
What students show: Test table, code or build revision, and evidence-based explanation.Materials
- Cardboard, paper, craft sticks, tape, reusable building pieces, and student-proposed materials
- Project platform: Cardboard mechanisms + optional 3D print or servo
- Breadboard, paper-circuit supplies, or low-voltage power when needed
- observed light direction or optional light sensors input component or student-designed substitute
- hand-adjusted mechanism or optional servo shade output component or student-designed substitute
- LEDs, resistors, jumper wires, copper tape, switches, and clips as needed
- 3D Printing materials for an optional case, sign, mount, or model
- Computer with approved coding or simulation tools when needed
- Planning sheet, ruler, and test-data table
Teacher preparation
- Build and test one possible reference solution without making it the required design.
- Prepare a basic-materials table plus optional electronics and fabrication stations.
- If coding is used, prepare a starter option for a position chart, mechanical rule, or optional servo commands; students may propose another workable control method.
- Prepare optional fabrication templates and a file rule beginning G3_09.
- Mark adult approval points before power-on and machine fabrication.
Step by step
How to teach it
Meet the user and define success
- Introduce the application: Keep a model playground seat shaded as the direction of a lamp changes.
- Identify the user, need, criteria, and constraints.
- Draw a system map with input → code → output.
Build a first solution
- Choose basic, electronic, and fabricated materials based on the team's idea.
- Build with power disconnected whenever electronics are used.
- Complete an adult check, then troubleshoot one connection or physical feature at a time.
Create the behavior
- Create the first working control using a position chart, mechanical rule, or optional servo commands.
- Predict what one rule, connection, or code change will do before testing it.
- Make the system understandable with labels, diagrams, comments, or coding blocks.
Test and improve
- Use the same procedure each time: move one lamp to three marked positions while keeping distance fixed.
- Record at least three results.
- Change one code, circuit, or physical-design variable and retest.
Fabricate and present
- Design a 3d printing part that protects, mounts, or explains the electronics.
- Adult reviews and operates fabrication equipment where required.
- Connect the finished system and demonstrate how the evidence improved it.
Assessment
- Problem statement names a real user and measurable need.
- Circuit matches the team diagram and uses components safely.
- Program connects the intended input to the intended output.
- Test conditions remain consistent and include recorded evidence.
- Revision addresses a documented failure or user need.
Supports & extensions
- Use color-coded wires and a photograph of each breadboard step.
- Provide block coding or partially completed code with one change at a time.
- Assign roles: circuit builder, coder, tester, and recorder.
- Let students explain findings orally or with labeled diagrams.
- Extension: add a second sensor, output, data display, or operating mode.
Safety & responsible use
- Use only teacher-approved low-voltage classroom electronics; never connect projects to wall current.
- Disconnect power before changing wires or components.
- Use the correct resistor with every standard LED and stop immediately if a part becomes hot.
- An adult handles soldering, laser cutting, printer setup, blades, and final power approval.
- Keep liquids away from boards unless a sealed, teacher-approved sensor activity specifically requires them.
No-machine alternative
Build with cardboard, paper mechanisms, paper circuits, or a free on-screen simulator. Students may invent another safe way to model the same function, then compare ideas, test one variable, collect evidence, and revise.
Printable student design brief
The challenge
Create a working solar shade tracker for this need: Keep a model playground seat shaded as the direction of a lamp changes.
Success criteria
- Shade adjusts toward the brighter side
- Covers the target area in all three tests
- Mechanism moves freely and safely
Constraints
- Begins with cardboard or reused materials
- Lamp remains cool and teacher controlled
- Teams decide whether fabrication or electronics improve the design