TWO CLOCKS. ONE REUNION. / TIME DILATION TEACHING KIT

Open lesson.html in a browser without needing a connection. Print PDF pages 1-4 for the core; page 5 is optional extensions. Pages 6-11 are educator/reference material. Use learner-responses.txt or paper. No account, payment, answer upload or 3D renderer is needed.

Primary level: grades 9-12, about 50-60 minutes. Teacher-led grades 6-8 enrichment and introductory-college/advanced-high-school extensions are described. Times are planning estimates.

Cases are generated, idealized teaching data, not observations. The main mission uses beta = 0.8, one-way distance 6 light-years, Earth send interval 0.5 year. This matches the lab automatic schedule for that mission. Verify the paper cases with python3 verify_analysis.py (Windows: py -3 verify_analysis.py). Python 3.9+ standard library only; no network calls.

The live lab is optional: https://darksciencedocs.com/exploration-guides/time-dilation/

See standards-alignment.json for task-specific mappings and accessibility-review.txt for concise completed review checks. The mapping is not certification or a complete NGSS performance-expectation claim. The PDF is tagged, not a scanned worksheet.

CC BY-NC 4.0 applies to original teaching materials; see EDUCATIONAL-USE.txt and visible PDF page 1/page 11 notices.
