E&M Lab

An interactive, intuition-first study site for AP Physics C: Electricity & Magnetism and the electricity and magnetism topics of AP Physics 2.

23 modules (Units 8 to 13, plus a small math toolkit), each with a live simulation (several in 3D), a "Try this" section, a worked example with a diagram, common mistakes and a quiz. Review tools: 102 randomized practice problems, "Which tool?" trainer, exam builder, spaced mistakes queue, four original FRQs with scoring guides, and a formula sheet.

Unofficial study aid. Not affiliated with, reviewed by, or endorsed by the College Board. Use it to study, not on graded work. The AP Physics 2 mapping was written from memory. Check topics against the current Course and Exam Description on AP Central.

Build

The site is one generated file, index.html, assembled from src/:

python3 build.py            # writes index.html

• src/a_head.html CSS, src/b_shell.html menu and dialogs, src/formula.html formula sheet, src/overview.html
• src/d_engine.js canvas helpers, src/f_helpers.js shared helpers, src/g3.js + src/hero.js overview scenes, src/h_tail.js practice, review, report and polish code
• src/course.js module list, units, glossary
• src/modules/<id>.html and <id>.js one pair per module. tools/gen_*.py generate the HTML (using tools/mk.py); edit those, then rerun them and build.py.

Quick regeneration: for f in tools/gen_*.py; do (cd tools && python3 $(basename $f)); done; python3 build.py (efield.html is hand-written).

Checks (need Node and Playwright)

• node tests/smoke.js [view,view] visits every view at desktop and phone width: duplicate IDs (case-insensitive), overflow, blank canvases, NaN text, JS errors, "Set it up for me" buttons.
• node tests/deep.js practice, exam, trainer, formula sheet, report dialog, every module's parts, FRQ graphs.
• node tests/probdump.js [topic] prints one sample of every practice problem for hand-checking.
• node tests/shot.js <view> out.png [width] [clicks] screenshots a simulation.

Reporting a problem

Every module and problem has a Report an issue link. It opens a pre-filled GitHub issue (or saves to the artifact database when hosted as an artifact).

Issues go to the shared Intulab feedback tracker, labelled course:em. You can also open one directly.

The More labs link in the side rail goes to the Intulab landing page. Visits are counted anonymously with GoatCounter (no cookies), shared with the other Intulab sites.