Privacy and terms

Short version: nothing about your child leaves your device. There are no accounts, no ads and no tracking. The only thing ever sent anywhere is a license key, if a grown-up enters one: it goes to Gumroad, our store, to check the purchase, and only after the grown-up agrees.

Who we are

Kindergarten Science Labs is made and sold by Abhishek Sinha. Questions about privacy, a license or a refund: reply to your Gumroad receipt email.

This website

k5stem.com, including the labs at k5stem.com/play, is a set of static pages served by Cloudflare. The website sets no cookies and uses no analytics, advertising or tracking. Like any web host, Cloudflare processes your device's IP address to deliver the pages and protect the site from attacks.

The website and the labs load nothing from other websites: no third-party scripts, fonts or images. Buy buttons are plain links that open Gumroad's checkout in a new tab; that checkout is run by Gumroad under its privacy policy. The only other request is the license check described below, made when a grown-up enters a key.

The Unlock page and the labs use the same browser storage on your device, described below, so a key entered on either one unlocks both.

What the app keeps on your device

The app saves the following in your browser's storage on the device you use. None of it is sent to us, and we can't see it.

• Which labs your child has finished (their badges), when each was first finished, and which badges the home page has already celebrated.
• Whether the home page's sound is turned off.
• For the open browser tab only (deleted when the tab closes): that the welcome line was already played, and that a grown-up answered the grown-ups question in the last 10 minutes.
• If a grown-up activates a license: the key, its plan, how many devices the plan allows, whether it was a test purchase, when it was activated and last checked, and how many checks in a row Gumroad didn't recognize it.
• When the grown-up agreed that the key may be sent to Gumroad.
• If a weekly check finds that the key no longer works (for example after a refund), the app deletes the key and its details by itself and keeps a short note saying why, shown on the Unlock page until a key is activated again.

The labs ask children to tap, not to type, and they never ask for a name. The name a grown-up types on the certificate is used only to print it and is not saved.

What leaves your device, and why

What

Your license key and our product ID

Sent to

Gumroad (Gumroad's privacy policy)

When

When a grown-up presses Unlock, after agreeing, and about once a week after that, when the labs are opened

Why

To check that the purchase is valid, so the labs unlock or stay unlocked

When you activate, the app first asks Gumroad to check the key. If the key is good and its plan has room, a second request adds this device to the key's count of devices. The weekly check only looks; it never adds a device. Like any internet request, each one also lets Gumroad see your device's IP address.

From Gumroad's reply, the app keeps only the plan, the number of devices it allows and whether it was a test purchase. It reads how many devices already use the key, to stay within the plan's limit, but doesn't store that number. It doesn't keep your email address or any payment details.

Nothing else is sent: no analytics, no advertising, no cookies, no tracking and no third-party scripts. The pictures, voices, fonts and icons are part of the app. Buy buttons and help links simply open Gumroad's website, and only from the grown-ups area.

When you buy

Gumroad runs the checkout and handles payment as the merchant of record; its privacy policy covers the details you give there. Gumroad shares the purchase details sellers receive, such as your email address, with us so we can help with your license, a device reset or a refund. We use them only for that, and we never sell them.

Children's privacy

The labs are made for children aged about 5 and 6, used with a parent or teacher. We don't collect personal information from children: nothing a child does in the labs leaves the device. Buying, license keys and links out of the app are for grown-ups and sit behind a grown-ups question.

Limited use

The use of information handled by Kindergarten Science Labs complies with the Chrome Web Store User Data Policy, including the Limited Use requirements. Data is used only to provide the labs and check your license. It is not sold, not used for advertising, not used to determine creditworthiness, and not transferred for any purpose unrelated to the app.

Deleting your data

• Grown-ups → Progress → Reset badges deletes your child's badges on this device.
• Grown-ups → Unlock → Remove the key deletes the license key and its details, and your agreement to send it to Gumroad.
• Removing the Chrome extension deletes everything it saved. If you use the labs from a folder or a website, clearing that site's data in your browser settings does the same.

To have your purchase record removed from our Gumroad account, contact us as above.

Terms of sale

• Seller. Sold by Abhishek Sinha through Gumroad, which processes the payment as merchant of record. Google is not the seller.
• Free. Push the Ball! works fully at no cost.
• Plans. One-time payments in US dollars, plus sales tax or VAT where it applies. Family, $19: one household, up to 5 devices. Classroom & Co-op, $49: one class, co-op or tutoring group, up to 30 devices. Both include all 8 labs and future updates to them.
• Devices. Each browser profile where you activate your key counts as one device. Removing the key from a device doesn't free the slot; contact us and we'll reset it.
• Refunds. If it isn't right for you, contact us within 30 days of buying for a full refund. A refunded or disputed purchase stops unlocking the paid labs.
• Fair use. Please don't share your key outside your plan or copy the app for others. Lab records and certificates are yours to print and share.

About the science

The labs are simulations made for young children. They follow real science closely but simplify it so the main idea stands out, and they work best alongside real hands-on play: each lab's grown-ups page suggests an activity to try. The app is provided as is, without warranties beyond those required by law.

*Next Generation Science Standards and NGSS are registered trademarks of WestEd. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.

Changes

If what the app does with data ever changes, we'll update this page and change the date below before the change takes effect.

Last updated November 10, 2026.