# Reality Check

- **Event:** [Meta Global AI Developer Hackathon](https://cerebralvalley.ai/e/meta-ai-developer-hackathon)
- **When:** Oct 26, 12:00 PM – Nov 4, 9:00 PM (EST)
- **Where:** Online
- **Team:** [Ethan Wong](https://cerebralvalley.ai/u/etw005)
- **GitHub:** https://github.com/ewong25-sudo/reality-check
- **Demo video:** https://youtu.be/A9SCT0KHxrA
- **Gallery:** https://cerebralvalley.ai/e/meta-ai-developer-hackathon/hackathon/gallery
- **Page:** https://cerebralvalley.ai/e/meta-ai-developer-hackathon/hackathon/gallery/4328

Reality Check catches AI-generated video by measuring whether it obeys real physics. AI video generators still get physics wrong: balls fall too slowly, gravity changes between bounces, and bounces gain energy from nowhere. Reality Check tracks a falling or bouncing object, fits each flight arc to the free-fall equation y(t) = y0 + v0·t + ½·g·t², and measures gravity directly. Real footage comes out near 9.8 m/s²; a clip where a ball falls at 2.9 m/s² is physically impossible, and Reality Check says so with the number to prove it.

Two supporting checks cover files without measurable motion: a provenance check that reads AI labels generators write into files (C2PA Content Credentials, IPTC "trainedAlgorithmicMedia"), and a visual inspection for generator watermarks and AI artifacts. The evidence is combined into one clear answer, AI-generated or Real, with a confidence and the reason, instead of an opaque score. It runs as a web app and as an iPhone app that shows the answer in the Dynamic Island when you share a photo or video.

Everything was built during the hackathon, with the help of an AI coding assistant. On synthetic test videos with known physics it scored 7/7 (4/4 fakes caught, 0 false alarms), measuring gravity on real-physics clips to within 3.1%.

## More from Meta Global AI Developer Hackathon

- [Interaction Twin](https://cerebralvalley.ai/e/meta-ai-developer-hackathon/hackathon/gallery/4325)
- [vivedex](https://cerebralvalley.ai/e/meta-ai-developer-hackathon/hackathon/gallery/4326)
- [Oja Ledger](https://cerebralvalley.ai/e/meta-ai-developer-hackathon/hackathon/gallery/4327)
- [vLock AI Vision](https://cerebralvalley.ai/e/meta-ai-developer-hackathon/hackathon/gallery/4329)
- [Agent Wallet Treasury x402](https://cerebralvalley.ai/e/meta-ai-developer-hackathon/hackathon/gallery/4330)
- [Melissa](https://cerebralvalley.ai/e/meta-ai-developer-hackathon/hackathon/gallery/4331)

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