Built in the classroom
Mistake Master is a free, browser-based AP Physics 1 diagnostic and adaptive remediation platform, written by a teacher actively using it with students. Every wrong answer maps to a named misconception. The platform drills the underlying confusion until the student clears it.
What it does for your students.
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 units (sign errors, conflating speed with acceleration, treating mass and weight as the same) get re-checked in every later context, so a code that looked cleared in kinematics has to survive forces, energy, and momentum too.
Browser-based. No accounts. Progress saves to the device.
Use it Monday morning.
Mistake Master is built to drop into the classroom without a setup process. Five real ways teachers are using it now.
Open the diagnostic for the unit you're in. Students get short, targeted items on active misconceptions. They're done before you finish attendance.
When a quiz reveals a misconception is widespread, route students into the remediation drill. Adaptive, so kids who already cleared it move through faster.
Cumulative diagnostic mode mixes items across all live units. The two-correct-in-a-row rule means students don't waste review time on what they already know.
Different students at different units, all working on what they actually need next. No setup beyond opening the link on each device.
Send the link. When students miss a question, the platform drills the underlying misconception until cleared. They show up the next day having done work that mattered.
The dashboard surfaces the active misconceptions per student. You walk into tomorrow's class knowing exactly what to address.
What students actually bring in.
These are six of the most common AP Physics 1 misconceptions in the platform. Each one has its own coded distractors, its own remediation, and its own re-check across every later unit where it surfaces. Field notes on each one 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 noteWhere it stands.
AP Physics 1 is the active build. Six units are live, wired end to end: diagnostics, adaptive remediation, and lessons. Unit 7 is in progress. Unit 8 is on the runway.
From the classroom.
Students recite that energy is conserved, then call a sliding block's energy gone the moment it stops. Naming the system that receives the energy is the move that fixes it.
Both read as how much motion, so students fuse them and use one conservation law to answer questions only the other can. The square in kinetic energy is what the intuition keeps dropping.
Common questions.
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.
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.