Privacy Policy.

We keep this deliberately small:

• Your email address and a username, so you can sign in and appear to friends.
• The answers you write, the marks and feedback you receive, and which questions you have attempted, so we can show your progress and let you review your work.
• Basic technical information needed to run the service (for example, a secure sign-in cookie).

We no longer ask for your school, year or subjects at sign-up. We do not ask for your full name, phone number, address or date of birth.

• We do not sell your data, or share it for advertising.
• We do not build a profile of you to target ads.
• We do not require any personal detail beyond an email and a username.

Particle's marking is extremely well calibrated to NESA's HSC marking criteria and guidelines, so its feedback closely reflects how the HSC is actually marked. To mark a written answer, we send the question and the text you wrote to a trusted third-party AI marking provider. They return a mark and feedback, which we save to your account. Under that provider's terms, your content is not used to train their AI models. Multiple-choice questions are marked instantly on our own servers and are not sent to any AI provider.

Because your answer is sent for marking, please do not include personal or sensitive information in your answers. Answers should be your Physics or Chemistry working, nothing more. See How Particle uses AI for more detail.

• Data is sent over encrypted connections (HTTPS).
• Accounts and data are stored with reputable, security-focused cloud infrastructure providers.
• Access is limited to what is needed to run the service and provide support.

If you subscribe to Premium, payment is handled by our third-party payment processor (Stripe). You enter your card details directly with them, over their secure systems. Particle never sees or stores your full card number. We only receive confirmation that a payment succeeded and a reference to your subscription, so we can turn Premium on for your account.

Particle is designed for senior high school students. If you are under 18, we encourage you to use Particle with the awareness of a parent, guardian or teacher. Because we collect so little, there is very little about you stored in the first place. A parent or guardian can contact us at any time to ask what we hold about an account, or to have it deleted.

You can, at any time:

• See your account details and your practice history in Settings and on your profile.
• Change your username or nickname.
• Ask us to delete your account and the data attached to it.

To request access, correction or deletion, email particlehsc@gmail.com.

We use a secure cookie to keep you signed in. We do not use advertising or third-party tracking cookies.

If we change how we handle your data, we will update this page and the date at the top. Particle operates from New South Wales, Australia, and aims to follow the Australian Privacy Principles.