fysiklab.dk
Fysiklab.dk is an interactive physics simulation platform. This page explains what data we collect and why. The Energy comparison uses sessionStorage to remember progress in the current browser tab; browser session restoration may retain it. Launch a satellite uses localStorage for best-effort mission resume across visits in the same browser on this site's origin (protocol, domain and port). Mission saves remain until you or your browser clear them; browser settings, storage limits or browser cleanup may prevent or remove a save. These saves stay on your device: they require no account, are not uploaded and are not used to track you across visits.
We use PostHog (EU servers) to count anonymous usage events — which simulations you open and which steps you click. This helps us understand which topics are most useful so we can improve the platform.
Some simulations include a tutor you can chat with. When you use it, we store your messages, the tutor's replies, and which simulation and step you were on — so we can read them to improve the tutor and catch wrong answers. Conversations may be read by the developer. We do not store your name or IP address with them. To produce each reply, your message is sent to Anthropic (USA) under a data-processing agreement with EU Standard Contractual Clauses; it is not used to train their models, and Anthropic retains it for up to 30 days for safety and security before deleting it. Conversations are stored on Supabase servers in the EU (Ireland) under a data-processing agreement. Please don't type personal information (name, class, etc.) into the chat.
Your IP address is transmitted to PostHog with each analytics event. PostHog uses it to derive an approximate country and then discards it. It is not stored as part of the event record.
Analytics are processed on the basis of legitimate interest (GDPR Art. 6(1)(f)) — specifically, understanding which simulations are used so we can prioritise improvements to the platform. The same basis covers the tutor conversations: we read them to improve the tutor and catch wrong answers.
Anonymous event data is retained for one year. Tutor conversations are retained for 12 months, then deleted.
You can request access to or deletion of your tutor conversations (GDPR Art. 15 and 17). Because we hold no account or name, please include the simulation and the approximate date and time of the conversation so we can find the record. Write to kontakt@fysiklab.dk.
You can also complain to the Danish Data Protection Agency: Datatilsynet.
Questions about this privacy notice?
kontakt@fysiklab.dk