Quick Answer: Tongjiang Lab offers 54 free 3D science lessons for high school physics, chemistry, biology and geography. The lessons follow China's national senior high curriculum and PEP 2019 textbooks. Each lesson is a single HTML file of about 1 MB that works offline in Chrome or Edge, so you can run free 3D science lessons on a projector without a live connection.
Most science demos die on the projector. The teacher spends eight minutes hunting for a video, the Wi-Fi drops, and the class stares at a static diagram of a galvanic cell. Tongjiang Lab takes a different approach. Each lesson is one 3D scene with a live control console, a guiding question, and a step-by-step path you can follow from start to finish. Here's what that looks like in practice and where it falls short.
Why a single HTML file changes classroom logistics
The most important design decision here isn't the 3D graphics. It's the packaging. Each lesson is a single HTML file, roughly 1 MB, so there's no server to configure, no account to create and no login screen eating the first five minutes of class.
Double-click the file, and it opens in the browser. When the network fails, the lesson still runs, which matters more than most edtech vendors admit. A lesson that depends on a live server fails at the exact moment you need it.
The common advice is to choose a hosted platform with accounts, dashboards and usage tracking. That advice assumes your school has stable connectivity and wants analytics. For a single teacher in a single room, a file you own is often more dependable than a service you rent. You trade away automatic updates and tracking, and that trade is worth stating plainly before you commit.
Each lesson includes a guiding question and a path of between 7 and 9 steps in the examples listed in the README. That structure suits a timed class period better than an open sandbox does, because you always know which step comes next.
What's covered: 54 lessons across four subjects
The catalog breaks down like this:
- Physics: 10 lessons, such as the photoelectric effect, self-induction and eddy currents, and projectile motion
- Chemistry: 25 lessons, including the Haber process, the chlor-alkali industry, and sulfuric acid by the contact process
- Biology: 5 lessons, including nerve impulse generation and observing mitosis in root-tip meristem cells
- Geography: 14 lessons, covering ocean currents, El Niño and La Niña, and karst landform formation
Chemistry dominates the catalog, and that's the first place to look if you're planning a unit. Biology is thin at five lessons. If your syllabus is broad, expect to fill gaps with other resources.
Every row in the README also lists the textbook location, such as "Required Vol. 2, Ch. 5, Sec. 1." That detail is useful. You can match a lesson to a specific section rather than guessing whether it fits your sequence. Verify that match against your own edition, though, because textbook revisions shift chapter numbers.
Here's the thing most people miss: chemistry lessons often repeat the same reaction family across different sections. The sulfur lesson and the sulfuric acid lesson overlap in oxidation-state reasoning. If you teach both, you can reuse the same mental model and save class time.
Choosing how to deliver the lessons
The README offers four access routes, and they're not interchangeable. Pick the one that matches your room, not the one that sounds most modern.
| Method | Best for | Needs internet? | Main caveat |
|---|---|---|---|
| Online at lab.tongjiang.app | Quick previews and planning at home | Yes | Depends on the site being reachable during class |
| Single lesson HTML download | One lesson on one projector | No, after download | You download each lesson separately |
| Full zip from Releases | Whole department or school-wide offline use | No, after download | Requires one download and local storage |
<iframe> embed | School website or LMS page | Yes | The page breaks if the host site is blocked |
For most teachers, the sweet spot is this: preview online at home, download the zip or the specific lesson file, and run it locally in class. That combination removes the single point of failure.
Running a lesson offline, step by step
The offline workflow is simple, but a few details decide whether it works on the day:
- Go to the Releases page and download the zip for all lessons, or download a single lesson from its page at lab.tongjiang.app.
- Unzip the folder to a local drive. Don't run it from a cloud-synced folder, because sync delays can make the file appear partially downloaded.
- Double-click the HTML file and open it in Chrome or Edge, as the README recommends.
- Run the lesson once on the actual projector or interactive whiteboard before class. Check the frame rate, the control console placement and the text size from the back row.
Here's the trap I'd warn you about. On GitHub, clicking an HTML file shows you its source code, not the lesson. The README says this directly, but people still click the file and assume the download is broken. Always use the lab.tongjiang.app links or the Releases download.
The Chinese-language interface is a real barrier
The lesson interface is currently in Chinese, and the README says other languages are planned. That's the single biggest limitation for non-Chinese-speaking teachers.
Who benefits most right now? Teachers at Chinese-medium schools, teachers working with Chinese-speaking colleagues, and students learning Chinese through science content. If you're outside those groups, you have two options. You can pair with a colleague who reads Chinese and have them pre-read the control labels. Or you can wait for the planned language support. Neither is ideal, but pretending the language barrier doesn't exist will waste your prep time.
Is it worth the effort? For the physics and chemistry lessons, probably yes. The visual content carries much of the meaning, and the step structure gives you a reliable sequence even if you can't read every label.
Embedding lessons in a school website or LMS
If your school runs a website or a learning management system, you can embed a lesson with an iframe. The README gives this pattern, with a 16:9 aspect ratio and fullscreen permission:
<iframe src="https://lab.tongjiang.app/<slug>" width="100%" style="aspect-ratio:16/9;border:0" allow="fullscreen"></iframe>
Replace <slug> with the lesson's identifier, which you can take from the lesson URL. Embedding is an online-only option. If the host site is blocked on school networks, the embed won't load, and the offline file is your fallback.
Check the README's catalog.json before you build a course page. It lists every lesson with its textbook location and steps, so you can generate a sequence or audit coverage without clicking through 54 pages.
Where the source stops and your judgment starts
The README tells you what the lessons are and how to access them. It doesn't tell you how each lesson performs on every projector, how well each simulation matches your textbook edition, or whether a given step suits your students' prior knowledge. I haven't verified those points, so treat the catalog as a starting map, not a guarantee.
Before you rely on any lesson in an assessed context, run it yourself, compare its content with your textbook, and decide where you'll add your own explanation. That's the honest workflow, and it takes less time than most teachers expect once you've done it for two or three lessons.
Frequently Asked Questions
What are free 3D science lessons for high school?
Free 3D science lessons are interactive simulations that teach a concept through a visual, manipulable scene instead of a static diagram. Tongjiang Lab provides 54 of them across physics, chemistry, biology and geography, aligned to PEP 2019 textbooks. Each runs as a single HTML file that works offline in Chrome or Edge.
Where can I find free 3D science lessons that work offline?
Download the full zip from the Tongjiang Lab Releases page on GitHub, or download a single lesson from its page at lab.tongjiang.app. Open the HTML file in Chrome or Edge. No internet connection is needed once the file is on your computer.
How do I open an offline science lesson in Chrome?
Unzip the downloaded folder, locate the lesson's HTML file, and double-click it. If it opens in another browser, right-click the file and choose Chrome or Edge. Run a test on your projector before class, because screen resolution can change how the control console displays.
Why does the lesson file on GitHub show code instead of the lesson?
GitHub displays HTML files as source code by default, so you see the markup instead of the rendered 3D scene. Use the lab.tongjiang.app link or the Releases download to run the lesson. This is a display behavior, not a broken file.
Are these lessons aligned with my textbook?
They're aligned with the Chinese national senior high curriculum and People's Education Press (PEP) 2019 textbooks, and each entry lists its textbook location. Check that location against your own edition, since chapter numbers can differ between revisions.
Try opening one physics lesson on your projector this week and time how long it takes to load and run from start to finish. Pass this to a colleague who's wrestling with a science lab that won't run on the school network, and point them to the free 3D science lessons on the Tongjiang Lab Releases page.