The Feynman Technique: Understand Any Course in 4 Steps

You can reread a chapter 10 times. If you can't explain it to your little sister, you haven't understood it.

This is the basis of the Feynman technique.

Richard Feynman, a Nobel Prize winner in physics, had an obsession: if you are not able to explain a concept in simple words, it means you don't really understand it. You're just pretending.

This method has become the best-kept secret of students in prep school, medicine, and law. And the good news is, it's ultra-simple.

Why the Feynman technique works so well

When you learn "passively" (reading, highlighting), your brain stores words. Not meaning.

When you explain a concept out loud, your brain has to: - connect ideas with each other - detect gaps in your understanding - rephrase with your own vocabulary

It's this last point that changes everything. Rephrasing = understanding.

A study from Stanford University showed that students who explain what they learn retain 90% of the content, compared to 10% for those who just read.

The 4 steps of the Feynman technique

Step 1: Choose a concept and write it at the top of a sheet of paper

Anything. "Photosynthesis". "The Pythagorean theorem". "The French Revolution of 1789".

You write the name of the concept at the top of a blank sheet of paper (or Notion doc, it doesn't matter).

Step 2: Explain the concept as if to a 12-year-old child

No jargon. No complicated words. No copying and pasting from the course.

You write, in your own words, as if you had to explain it to a curious kid.

Example: instead of writing "Photosynthesis is a bio-chemical process by which autotrophic organisms synthesize organic matter", you write "Plants eat light. They take sun, water, and air, and they make their food."

If you struggle to simplify → it means you don't understand. That's the purpose of the exercise: to find your gaps.

Step 3: Identify bottlenecks and go back to the course

Everywhere you stumble, where you reuse jargon without being able to simplify it, where you go "uh..." → that's a gap.

You go back to your course. You reread only the part that is causing the problem. You understand. You come back to your explanation.

Step 4: Simplify further, and test with analogies

You go over your text again. You remove any remaining complicated words. You add concrete comparisons.

"Electrons orbit the nucleus" → "Electrons orbit the nucleus like the Earth orbits the Sun."

Bonus level: read your explanation out loud to a friend. If there's a question you can't answer, go back to the course.

Concrete example: explaining the Pythagorean theorem with the Feynman technique

Step 1: Pythagorean theorem

Step 2 (rough draft): "In a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides."

That's too technical. Let's simplify.

Step 3 (Feynman version): "In a triangle that has a right angle (a very square, 90° angle), there is one side longer than the others: the hypotenuse. If you take this long side and multiply it by itself, you get the same number as if you multiplied the other two sides by themselves and added them together. If the sides are 3 and 4, the long side is 5. Because 3×3 + 4×4 = 25 = 5×5."

Step 4 (analogy): "It's like walking diagonally across a yard: it's always shorter than going around the edges. Pythagoras tells you exactly how much distance you save."

When to use the Feynman technique

Conceptual concept (sciences, philosophy, economics, law) → the method is perfect.

Pure rote learning (vocabulary, formulas, dates) → less useful, prefer flashcards and active recall.

Before an oral presentation → essential. You work on your flow and detect your gaps.

Errors to avoid

Copying the course while thinking you are simplifying. If your sentences look like the course, you just copied. Force yourself to use different vocabulary.

Skipping Step 3. This is the most important step. Identifying gaps = 80% of the value of the method.

Doing it silently in your head. You have to write. Or speak out loud. In your head, your brain cheats, making you believe you know.

Winning combo: Feynman + active recall + Koro AI

The Feynman technique makes you understand. Active recall and spaced repetition make you remember.

The problem is time: to do Feynman correctly, you need a well-organized course, questions to ask yourself, and key points to isolate.

Koro AI transforms your course into a clear sheet in 30 seconds, generates the questions you need to ask yourself, and takes you from "I read" to "I understood" without working 3 hours to prepare your review.

You read the sheet. You close the app. You explain. You verify.

Test Koro AI →

Conclusion

Feynman technique = explaining a concept as if to a 12-year-old kid. If you struggle, you have a gap. Back to the course, you fill it, you explain again. That's all. But that's exactly what separates students who know from those who understand.