One browser tool for each topic in the AP Biology course, built by a teacher for a fourth-period classroom, and checked the way a worksheet is checked: against the course description and against real students.
A diagram shows a student the answer. A tool lets the student change something and watch what happens. So every interactive here is built around one variable the student controls: the solute concentration outside a cell, the temperature an enzyme is working at, the allele frequency going into the next generation. The student makes a prediction first, acts, and then compares what they predicted with what the model did. When the two disagree, that gap is the thing to go read about.
The handout is the paper trail. It carries the same prompts and the same data table as the tool, in the same order, so a class set prints two-sided and grading stays quick. Each topic has a student handout, a teacher key and a homework edition.
Each tool starts from the topic's learning objective and essential knowledge in the College Board course and exam description. The first decision is which single variable the student should control and what they should be able to say afterwards that they could not say before. That decides what gets drawn.
Where a tool runs a calculation, the model is checked before any drawing exists. The water-potential tool, for example, had its solute-potential equation verified against hand calculations and tested across ninety combinations of concentration and temperature before the first cell was drawn. Then the tool is built, the handout is written against it prompt by prompt, and the key is worked from the tool rather than from memory.
On AI. The code for these tools was written with Claude, an AI model made by Anthropic, working from my specifications, sketches and corrections. I decide what each tool should teach, what the student should control, and what counts as a right answer; I test each result several times over and send back what breaks. Nothing here requires a student to use AI, and no tool connects to one. Everything a tool needs is in its one file.
Classroom use is the first check, and the best one. The second is a unit-by-unit audit of every tool, handout and key against the 2025 course description: wrong answers, verdict text that gives the answer away before the student acts, labels that overlap on a phone, learning-objective wording that has drifted from the current CED. Problems are reported before anything is changed, and each unit's corrections are summarized in a one-page change note for teachers. Unit 2 was the first unit through; the others follow in order.
A small group of teachers try rough versions of new tools before they go public. If you would like to be one of them, or just want a short email when a unit is corrected, there is a form for that. It is the only thing the list is used for.
The site is a folder of static files served from a content delivery network. There is no database, no login and no account, so there is nothing to collect student data into. Share a link, project it, or put it in Google Classroom; the student opens it and starts working.
The tools and handouts are free to use, copy and modify for your own classes. If you find an error, or want a tool that does not exist yet, tell me through the form above. I would rather hear it than have it quietly not work in someone's fourth period.