Mistake Master
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Field notes

Short posts from an active AP Physics 1 classroom. The misconceptions students actually bring in, what their wrong answers reveal, and how the diagnostic is built to drill them out.

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From the classroom

Misconception Unit 1 May 8, 2026

Slope vs. area on v-t graphs: whichever the eye reaches first

Velocity-time graphs encode three quantities, and students reach for whichever one the graph makes most visually salient. With a sample item designed to separate the slope failure from the area failure from the read-the-y-value failure.

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Misconception Unit 2 May 8, 2026

Action-reaction "cancel out": why the third law looks like it predicts zero net force

The phrase "equal and opposite" sounds exactly like the language used for forces that cancel. Until students are forced to ask which object each force acts on, the third law looks like a contradiction.

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Misconception Unit 2 May 8, 2026

Mass vs. weight: the kg-vs-N gap that breaks every dynamics problem

Everyday English uses one word for two physical quantities. Until a problem leaves Earth's surface or asks for an FBD label, the conflation costs nothing. Then it costs everything.

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Misconception Unit 2 May 8, 2026

Centripetal as an extra force: the FBD entry that doesn't exist

The textbook introduces centripetal force as a force law with a formula, looking identical to gravity and friction. Students draw it as a fifth arrow on the FBD, and the radial equation has too much in it.

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Misconception Unit 1 May 5, 2026

Velocity vs. acceleration: the Unit 1 trap that hides all year

When students treat velocity and acceleration as the same vector, every later unit fights uphill against a confusion that should have been cleared in kinematics. Why it happens, what the wrong answers reveal, and where the platform drills it.

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Misconception Unit 1 May 5, 2026

Position, distance, displacement: three words, three meanings, constant trouble

In English, they're synonyms. In physics, they aren't, and that gap shows up every time a problem has a turnaround. With a sample item that lets you see which of the three a student is actually confusing.

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On deck

Coming next

Drafting Why wrong answers aren't random
Planned How to use Mistake Master for a 10-minute warm-up
Planned Why two correct in a row is better than one
About

What field notes are

These aren't a blog about teaching. They're a focused log of misconceptions seen in a working AP Physics 1 classroom, written with other teachers in mind. Each note follows the same shape: the mistake, why it makes sense to the student, the correction, a sample item, what each wrong answer reveals, and where the platform handles it.

If a misconception you see in your room isn't here yet, the email's on the teacher page. Send it over.