Choose a module

Where does your
reasoning need work?

Six classic misconceptions. Each one is more common than you think. Pick a subject and start explaining — honestly.

Physics
Electric Circuits
Series circuits, current, voltage — and why resistors don't 'use up' electricity.
Calculus
Derivatives
What f′(x) actually measures — and why it's not the same as plugging into f(x).
Chemistry
Stoichiometry
Limiting reactants, mole ratios — why comparing raw moles is the wrong move.
Biology
Cell Osmosis
Why water moves across membranes — and what 'concentration' really means here.
Mechanics
Newton's Laws
Action-reaction pairs — why a truck and a bug exert the same force on each other.
Algebra
Quadratic Functions
Why the roots of x² - 5x + 6 are not found by plugging in x = 5 or x = 6.