The Feynman Technique: If You Can't Explain It Simply, You Don't Know It

It is possible to sit through a class, nod along, and genuinely feel like you understood everything — and then freeze the moment an exam asks you to explain the same idea in your own words. That gap between recognising an explanation and producing one is where most half-understood topics hide, undetected until the worst possible moment.

The Feynman technique, named after the physicist Richard Feynman, closes that gap directly. Instead of asking "do I understand this?", you force yourself to actually explain the topic in plain language, as if teaching it to someone with no background in the subject. Every place the explanation gets clumsy, vague, or stuck is a precise map of what you still need to learn.

Step one: pick a topic and explain it cold

Choose a specific topic from your syllabus — not a whole subject, one clear concept, such as "Newton's second law" or "the causes of the French Revolution". Take a blank page and write or speak an explanation of it from memory, in the simplest words you can find, as though explaining it to someone younger who has never heard of it.

Do not open your notes yet. The point of this first pass is to reveal, honestly, exactly how much of the topic you can currently produce without help — which is usually less than you expected.

Step two: find where the explanation breaks

Read back what you wrote and mark every place where you reached for a technical term without explaining it, skipped a step because you were not sure of it, or wrote something vague like "and then this happens" without saying how or why.

• A jargon word you cannot define simply is a gap.
• A skipped step ("obviously...") is usually a step you do not actually follow.
• A vague connector phrase is standing in for something you have not worked out.

Step three: go back to the source and refill the gaps

Now open your textbook or notes, but only to fix the specific gaps you just found — not to re-read the whole chapter. Look up the exact term you could not define, the step you skipped, or the mechanism you glossed over, and add it back into your explanation in plain words.

This targeted return to the source is far more efficient than a general re-read, because you already know precisely what you are looking for and why it matters.

Step four: simplify and use your own analogy

Once your explanation is complete and accurate, rewrite it to be shorter and simpler still. Replace any remaining technical language with everyday words, and try to find one analogy from ordinary life that captures the core idea — electric current explained as water flowing through a pipe, for instance.

A good analogy is not decoration; it is proof that you have translated the idea into a mental model that is genuinely yours, not borrowed from the textbook's phrasing.

Using this technique efficiently

You do not need to run the full four steps on every single topic — save it for the ideas that feel shaky, that keep tripping you up in practice questions, or that carry heavy marks in the exam. Ten minutes of Feynman on your three weakest topics each week is a better use of time than running it on everything.

Keep the finished plain-language explanations in a notebook. In the days before an exam, reading five of your own simple explanations refreshes understanding far faster than re-reading five textbook chapters.

Frequently asked questions