Terms of use

Last updated October 29, 2026

Mr. Keye Physics is a free site I made for learning physics. It's my own personal project: it isn't run, owned, or endorsed by any school or school district. By using the site, you agree to these terms.

Use it to learn

Anyone is welcome to use the site. Its main purpose is to give students high-quality resources for learning physics.

No guarantees

I check the problems, solutions, and tools carefully, but mistakes happen. The site is provided "as is," without warranties of any kind. An answer checker can mark a right answer wrong (or a wrong one right), and the simulations are simplified models for learning, not tools for engineering or safety decisions. In a class, your teacher's grading is what counts.

Your work is saved only in your browser, so it's lost if your browser's data is cleared. Download a copy of anything that matters.

Lab safety

Some pages work with real hardware. Keep projects low-voltage, never connect a project to wall power, and if you're in a class, follow your teacher's lab rules. Uploading code or firmware replaces what's already on a board.

The Arduino compiler

The Compile button is for my in-person students. The compiler is only on during class, and I may limit or block any other use of it.

Unless a page says otherwise, the lessons, practice problems, solutions, and videos on this site are © 2026 Matthew Keye and licensed under Creative Commons Attribution-NonCommercial-ShareAlike 4.0 (CC BY-NC-SA 4.0). You're welcome to share and adapt them, in your own class for example, as long as you:

credit them to "Matthew Keye, Mr. Keye Physics (mrkeyephysics.com)," link to the license, and say if you changed them,
don't sell them or use them in anything that's sold, and
share anything you make from them under the same license.

The site's software, including the editors, simulations, and lab tools, is © 2026 Matthew Keye, all rights reserved. You're welcome to use it here on the site. Anything on a page that's credited to someone else keeps its own license.

Software and fonts by others

The site is built on open-source software and fonts, each under its own license: Astro, Preact, Tailwind CSS, KaTeX, Lucide, and jQuery (MIT or ISC); the Ace editor and Vernier's Go Direct library (BSD); GlowScript (MIT); Pyodide (Mozilla Public License 2.0) and the Python packages it runs; and the fonts Source Sans 3, Fira Code, IBM Plex Mono, JetBrains Mono, Source Code Pro, and Space Mono (SIL Open Font License) and Ubuntu Mono (Ubuntu Font License). More detail is in the third-party notices.

Trademarks

Arduino, Raspberry Pi, Vernier, and other product names belong to their owners. Mentioning them doesn't mean they're connected to this site or endorse it.

Links to other sites

Links to other sites are here because they're useful. I don't control those sites and I'm not responsible for them.

Accessibility

I want everyone to be able to use this site, including with a screen reader or other assistive tools, and I fix accessibility problems as I find them.

Limits

As far as the law allows, I'm not liable for any loss or damage from using this site, including lost work or damaged equipment.

Changes and law

I may update these terms; the date at the top shows the current version. These terms are governed by the laws of California.