Your class, by its mistakes.
Every wrong answer is tagged to a named misconception. The console turns that into a live map of who is stuck on what, and hands you the practice to fix it.
From wrong answers to your next move.
Students practice, their wrong answers map to misconceptions, and the console turns that into a teaching plan. Three steps, and nothing to grade.
The misconception map ranks every active confusion by how many students have it, so you walk in knowing what to teach first.
Cluster the students who share a trap into a reteach group, or mix strengths for balanced groups. Move anyone by hand.
Generate a worksheet with a teacher answer key for that group or misconception. Save as PDF or print it.
What powers the map.
Every wrong answer choice on this site maps to one named, research-anchored misconception. When a student misses a question, they don't just see the right answer. They get adaptive remediation that drills the underlying confusion until they've cleared it.
The mastery rule is simple: two correct in a row clears a misconception from the active queue. Items that recur across a course get re-checked in every later context, so a misconception that looked cleared early has to survive every later unit too. In physics, for instance, a sign error cleared in kinematics still has to hold up in forces, energy, and momentum.
Browser-based. No accounts. Progress saves to the device.
What students actually bring in.
Physics is the first subject built into the platform, and these are six of its most common traps. Each has its own coded distractors, its own remediation, and its own re-check across every later unit where it surfaces. The same misconception-coded approach carries to each new subject as it comes online. Field notes are going up as they get written.
Students treat velocity and acceleration as the same vector. If velocity is zero, they say acceleration is too.
Read field noteDistance and displacement are synonyms in the student's head. The gap shows up every time a problem has a turnaround.
Read field noteStudents use the words interchangeably. The trap survives Unit 1 unbothered, then breaks in forces and again in gravitation.
Read field noteStudents claim third-law pairs cancel each other, so net force is always zero. The pairs act on different objects, but that's not what they hear.
Read field noteOn a velocity-time graph, slope gives acceleration and area gives displacement. Students read whichever the eye reaches first.
Read field noteStudents draw a centripetal force on the FBD as a separate arrow alongside tension or gravity. It's the net force in disguise, not a new one.
Read field noteCommon questions.
Can I track my class's progress?
Yes. Create a class in the teacher console and share a join code. As students practice, a live gradebook shows skill-check mastery and scores, and a class misconception map ranks the confusions worth teaching first. No student emails or accounts.
Can I group students and assign targeted practice?
Yes. The console can cluster students who share a misconception into a reteach group, or mix strengths for balanced groups, then generate a printable practice worksheet with a teacher answer key for any group or misconception.
Is Mistake Master free?
Yes. Fully free, with no accounts required, no email walls, and no paid tier. It's built and maintained by a working classroom teacher.
Do students need to create an account?
No. Students can start using Mistake Master immediately by visiting the site. Progress saves to the device. Cross-device sync is on the roadmap.
Does it work on Chromebooks and iPads?
Yes. Mistake Master is browser-based, with no installs and no special permissions. It runs on Chromebooks, iPads, laptops, and phones.
How long is a typical session?
A unit diagnostic runs 5 to 10 minutes. Remediation drills typically run 1 to 3 minutes per active misconception. Students can use it in 10-minute warm-ups or longer review sessions; the platform picks up where they left off.
How does this align with the AP Physics 1 Course and Exam Description?
Items are mapped to AP Physics 1 essential knowledge points and learning objectives. The platform is algebra-based throughout, with no calculus notation, matching the AP Physics 1 specification.
How is this different from Khan Academy or AP Classroom?
Khan Academy is a video and practice library. AP Classroom is the College Board's official progress-check system. Mistake Master sits between them: every wrong answer choice is mapped to a specific named misconception, and the platform adaptively drills the underlying confusion until the student clears it twice in a row. The misconception-coded distractor design is the key difference.
Can I assign specific units or topics?
Yes. Each topic and unit has a direct URL. Share the link to a specific diagnostic, lesson, or interactive with your class.
Why I'm building it.
Mistake Master started as a problem set I was hand-coding for my own classroom. The misconception coding came from teaching the same units year after year and noticing that students made the same wrong moves in the same places. Once that coding was there, adaptive remediation followed naturally.
It's a platform now, but it's still the same project: a teacher trying to make wrong answers do real pedagogical work, not just count against a score.
Create your class in under a minute.
Free, with no student accounts, on any Chromebook or iPad. Share a join code and the misconception map starts filling in.
Get in touch.
I'd love to hear from you. Especially: errors you spot in the diagnostics or lessons, ways you're using it in your classroom, misconceptions I missed, and anything else worth saying.