Privacy policy

The short version

• We don’t sell your personal information, and we don’t use it for advertising. We load no advertising tags on any page.
• You can play the free games and work through the free pH module without an account or an email address.
• We ask for an email address when someone buys access, and for a teacher’s details when a teacher applies for a free account. We don’t ask for a mobile number.
• Email support@periodicmole.com and we’ll send you a copy of your data or delete it within 30 days.

What we collect

When you use the site without an account. We put a random ID in a cookie on your browser, so we can keep your progress there. Under that ID we keep:

• your progress: your answers in lessons, checks, reviews and games, your scores, which elements you’ve mastered, your review schedule, and how long you spent on each part;
• on the periodic table quiz, what you type for each element (up to 120 characters). We use the answers to build the Element Miss List, and we publish only counts of wrong answers that are themselves element names;
• which games you start and finish, which pages and prompts you see and tap, the site or link that brought you here, your browser type and language;
• the city, region and country our host works out from your IP address, which we store with each game you play.

When you join our Prolific panel study. We also keep your Prolific participant ID alongside your quiz run, answers and browser or account ID. We use it to assign your quiz questions, approve participation and exclude invalid runs. We publish only aggregate results, not participant IDs.

Progress without an account stays in that browser. To keep it across devices, a student needs an account.

When you have an account. We keep your email address, the name you give us, your password (stored only in scrambled, hashed form), your exam date, a study plan you write, your progress, and the same visit records as above. We record each sign-in with its IP address and browser, and we remember the browsers you’ve verified. When you sign in on a new browser, we email a code to your address. If a parent buys access for a student, the parent gives us the student’s email address, and we create the student’s account. We used to ask buyers, students and teachers for a mobile number. If you gave us one, we still hold it but no longer use it to sign you in, and we’re deleting the numbers we hold.

When you buy. Stripe collects your card details on its own checkout; we never see the full card number. We keep a record of the purchase: the plan, the amount, the dates, Stripe’s reference numbers, and the buyer’s email address. We also keep the notices Stripe sends us about each payment, which can include the buyer’s name, email address, billing country and postal code.

When you’re a teacher or a parent. When a teacher applies for a free account or asks for printables, we keep the teacher’s name, email address, school, class and approximate location (city, region and country). If a teacher asks us to mail a printed poster, we keep the school’s mailing address. When anyone gets the mole poster by email, we keep the email address, the role they pick (teacher, parent or student), and approximate location.

The 2026 contest. For the Element Mastery Prize, which closed on September 15, 2026, we kept the parent’s name and email address, the student’s email address, the state, and the IP address the parent consented from. Where a parent opted in, we show the student’s first name and state on the race page.

Written answers. When you write an answer to a written question in a Regents module, the text stays in your browser. We keep it only if you said yes to research notes (below). We don’t send what you write to any AI service.

Email. When we email you, we record that we sent it and whether it arrived. We keep no record of whether you open our emails or click their links. If you write to us, we keep your message.

How we use it

• To run what you asked for: keep your progress, schedule your reviews, sign you in, run multiplayer matches, and handle purchases and refunds.
• To email you: sign-in links and codes, account notices, and, for account holders, occasional progress emails, which you can turn off on your profile page. If you ask for the mole poster or printables, or sign up for teacher emails, we may email you new printables and teacher resources, each email with an unsubscribe link.
• To keep the site safe: we check for bots, limit password guessing, and ask for a code on a new device.
• To understand how people use the site, so we can make it better: we count visits and game plays, and we look at where visitors came from and which pages they tap through.
• To publish the Element Miss List, from quiz answers, as described above.
• To keep research notes, only for a student who says yes (below).

We don’t sell your information, and we don’t use it for ads.

Research notes on the Regents modules

Before a Regents module, we ask the student whether we may keep notes on how they use the lessons: what they answer and type, how long they spend on each part, which extra help they open, how they rate the lessons, how they feel about chemistry, and anything they tell us was confusing. We use the notes to improve the lessons. Under New York law the choice is the student’s, and if the student says no, we change nothing about the lessons, the reviews or the student’s progress. A student can turn the notes off with one tap at the foot of the module, and we then delete the notes we kept.

Companies that handle it for us

We use these companies to run the site:

• Vercel hosts the site, so it receives every request, including your IP address. We also use Vercel Web Analytics to count page views, and Vercel BotID to check for bots.
• Turso hosts our database.
• Stripe processes payments.
• Twilio used to text our sign-in codes, so it holds the mobile numbers it texted. We send it nothing now.
• Resend sends our emails, so it receives each address and message.
• Cloudflare runs multiplayer matches, so it receives a match token that identifies your browser or account.
• Google serves the site’s fonts (Google Fonts), so it receives your IP address and browser details when a page loads.
• Amazon Web Services stores the mole poster file, so it receives your IP address when you download it.
• Have I Been Pwned checks a new password against known data breaches. We send it the first five characters of the password’s hashed form, never the password.

We share personal information with anyone else only when the law requires it. If another company ever takes over Periodic Mole, your information would go to it under this policy.

Cookies

We set these cookies, and none is for advertising:

• pmole_session, a random ID we keep your progress under in this browser when you have no account. It lasts a year, or longer while it holds a no to research notes, so we don’t ask again too soon.
• The sign-in cookie, so you stay signed in. It expires after 30 days without a visit.
• pmole_dfp, a random value we use for a year to recognize a browser you’ve already verified with a code.

Stripe sets its own cookies on the checkout page, to prevent fraud. Vercel runs a bot check (BotID) in your browser on every page. Vercel says it sets no cookies for Web Analytics.

Do Not Track and Global Privacy Control

If your browser sends Global Privacy Control, we treat it as a no to research notes: we don’t ask, and if you said yes earlier, we turn the notes off and delete them. You can still turn them on yourself. We don’t change anything when a browser sends Do Not Track, because we load no advertising tags and don’t follow you across other sites.

Children under 13

Periodic Mole is made for high school students. It isn’t meant for children under 13, and we don’t ask anyone’s age. If we learn that a user is 12 or younger, we stop collecting their information and delete what we hold about them within 30 days. If you’re a parent and think your child under 13 is using Periodic Mole, email support@periodicmole.com.

How long we keep it

• Accounts, their progress and research notes: while the account exists, until you ask us to delete it. A student can turn research notes off at any time, and we delete them then.
• Progress and visit records without an account: under the browser’s ID. We don’t yet delete these on a schedule.
• Panel quiz runs, answers and Prolific participant IDs: we do not yet delete these on a schedule. You can ask us to delete them using the contact details below.
• Purchase records: as long as we need them for tax and accounting, even after we delete the rest of an account.
• Teacher, poster and contest details: until you ask us to delete them. When you unsubscribe, we stop the emails.
• Some records we keep briefly: the retry key for a graded answer for 7 days, and taps on the Topics & resources page for 90 days.
• The companies above keep their own logs, and Resend keeps copies of the email we send, under their own retention settings.

When we set shorter periods, we’ll list them here.

See, correct or delete your data

Anyone can ask, wherever they live. Email support@periodicmole.com and tell us what you want:

• a copy of the personal information we hold about you;
• a correction (you can also change your name and email on your profile page);
• deletion of your account and data.

We answer within 30 days. We may ask you to write from the account’s email address, so we know the request is yours. A parent can ask for their child. On your profile page you can also turn off progress emails, sign out of other devices, and forget a verified browser. Without an account, we hold no name or email for your progress, so tell us anything that helps us find it.

We don’t sell personal information. If you want to tell us not to anyway, write to the same address and we’ll record it.

How we protect it

We use HTTPS on every page, store passwords only in hashed form, and ask for a code we email when someone signs in to an account on a new device. No system is perfectly secure. If we learn of a breach of your information, we will tell you.

Changes to this policy

When we change this policy, we post the new version on this page with a new effective date. If we change how we use information we already hold, we’ll email account holders first.

Contact us

Stone Giant Studio LLC runs this site. Write to support@periodicmole.com with any question about this policy or your information, or by mail to Periodic Mole · 16801 Addison Road, Addison, TX 75001. The rest of what you and we agree to is in our terms of service.