Creature LabMake it. Meet it. Explain it.
An 80-minute Informatics lesson for Grades 7–8. Students work in pairs with a phone or tablet and one printed image target.
Before the students arrive
- Keep cab-ad powered on and connected to the internet. Share the HTTPS lab link or display the joining QR below. Students do not need Tailscale or an account.
- Print one target sheet per pair on plain, matte paper. The patterned square is the tracking target; the QR only opens the website.
- Try the complete flow on representative student phones: open the lab in Safari or Chrome, adjust a value, enter AR, allow camera access, find the target, cover it, then stop the camera. Browser simulation is useful but does not prove physical-phone performance.
- Check that the school network allows the lab URL and that browsers can save/download a text file. Bring a spare device for pairs whose camera or browser is incompatible.
- Ask pairs to alternate as designer and tester. Choose Grade 7 or Grade 8 in the workbench. The design and notes save in that browser; shared devices share this browser's saved work.
Open cab-ad.tail59f2ba.ts.net
Learning intentions
- Describe camera input, image recognition, and the displayed AR output.
- Predict how coordinates, scale, and animation speed affect an object.
- Change one variable at a time and explain a fix with evidence.
- Grade 8: distinguish an observation from an explanation and express target detection as an IF / ELSE rule.
Period 1 · Discover and design
| Minutes | Activity | Prompt |
|---|---|---|
| 0–8 | Reveal a creature on the printed card. Move or cover the card. | “What is the camera recognizing? Predict what happens when I hide the card.” |
| 8–15 | Explain input → process → output. Separate the physical card from the digital creature. | “Is the creature inside the paper? Where is the digital content?” |
| 15–30 | Pairs name and customize a creature. Predict, then change scale, X, or Y. | “Which value changed? What stayed the same?” |
| 30–40 | Swap designer/tester roles. Test in AR and enter field notes. | “Show the result. Explain one value without pointing at its label.” |
Period 2 · Investigate and debug
| Minutes | Activity | Prompt |
|---|---|---|
| 0–10 | Investigate tracking by changing distance, angle, or partial covering. Record the condition and result. | “How can we make this a fair test?” |
| 10–25 | Open Missions. Predict, load a broken creature, change only the named parameter, test, and explain. | “What evidence shows your change fixed the problem?” |
| 25–35 | Pair showcase: demonstrate a design decision and one debugging explanation. | “Could another pair reproduce your test?” |
| 35–40 | Download the learning log and submit through your usual class platform. Ask the exit questions below. | “What does the camera recognize? Which value did you change? What did you observe?” |
Mission checks and teacher answers
The app checks the numeric fix and that evidence was entered. It does not judge whether a student's explanation is scientifically sound. Read the learning logs and ask students to demonstrate their reasoning.
| Mission | Accepted fix | Look for in the explanation |
|---|---|---|
| Too big to land | Scale 0.45–0.85; other numeric and movement settings unchanged. | A smaller scale reduces the object's dimensions proportionally. |
| Lost off centre | X and Y within ±0.15 of zero; scale and movement unchanged. | X is horizontal, Y is vertical, and zero centres the object on its anchor. |
| Dizzy creature | Speed 0.3–1.2, still using Spin; position and scale unchanged. | A lower speed lengthens each rotation, making movement slower. |
Assess the thinking
Ask for one justified prediction, an identifiable variable change, an observation, and an explanation connecting the change to its result. A useful answer includes before/after values. Colour choices alone do not demonstrate these learning intentions.
Grade 7: explain one coordinate or scale change and solve one mission. Grade 8: solve all three, compare a prediction with evidence, and complete the tracking IF / ELSE description. The rule is a written explanation of the app, not student-authored executable code.
If something goes wrong
- No permission prompt: use the HTTPS link in the full Safari or Chrome browser. Check the site's camera permission in browser settings. Close other apps using the camera.
- Target not found: check that you are scanning the large patterned square, not the joining QR. Keep the whole square visible; move slowly; try even light and a different distance.
- Creature is huge or off screen: return to the editor and check scale, X, and Y. A mission may have deliberately loaded a broken design.
- 3D is slow: pause motion, close other browser tabs, or use a partner device. Use the preview and written notes if a device cannot track.
- Site is offline: check cab-ad's power and internet connection. An already open page may keep its editor, but this lab does not promise offline operation.
- Work disappeared: check that the same browser is being used. Private browsing, storage restrictions, or clearing browser data can remove progress. Download learning logs before returning shared devices.
Data and camera use
The lab has no accounts, analytics, database, or upload endpoint. Camera frames are processed in the browser. Creature settings, mission evidence, and notes are saved in browser storage when available. A shared creature link contains its name and design values, but no field notes. Learning logs download to the device; students submit them through your normal class process. Do not put personal information in creature names.
The camera starts after a student presses Start camera. Stop camera returns to the editor. Leaving or backgrounding the active AR page stops its stream and returns to the editor; students start it again explicitly.
How the lab is built
Static HTML and JavaScript with locally hosted A-Frame 1.6.0 and MindAR 1.2.5. The custom target is precompiled. No library downloads from third-party CDNs are needed during the lesson. See credits and source references.