I Tried the Feynman Technique on My Hardest Subject — Here's My Honest Take

I'm a CS student, and I was struggling with a theoretical algorithms course. I could follow the proofs in class, but when I sat down to do problem sets, I'd blank. I knew the steps but not the why behind them.

A professor mentioned the Feynman Technique in passing — the idea of explaining a concept as if teaching it to someone with no background. I decided to try it properly for one week before my midterm.

What the Feynman Technique Actually Is

The Feynman Technique is named after physicist Richard Feynman, who was famous for his ability to explain complex ideas in simple terms. The technique has four steps:

1. Choose a concept you want to understand.
2. Explain it as if you're teaching it to someone with no background (often described as "a 12-year-old").
3. Identify the gaps — the places where your explanation breaks down or you have to use jargon you can't define.
4. Go back to the source material to fill those gaps, then try again.

The key insight is that jargon is a hiding place for confusion. When you can't explain something without technical terms, it usually means you understand the label but not the underlying concept.

What I Actually Did

I took the five hardest concepts from the course — dynamic programming, NP-completeness, graph traversal, amortized analysis, and randomized algorithms — and for each one, I opened a blank document and tried to write an explanation that a smart high school student with no CS background could follow.

No notes. No textbook. Just me and a blank page.

What Happened

It was humbling. I thought I understood dynamic programming. I'd done the problem sets. But when I tried to explain why it works — why breaking a problem into subproblems and memoizing the results gives you the right answer — I couldn't do it without reaching for jargon.

That gap — the moment where I had to use a technical term because I couldn't explain the underlying idea — was exactly what the technique is designed to expose. I went back to the textbook specifically to fill that gap, not to re-read the whole chapter.

For NP-completeness, I discovered I'd been using the term correctly without actually understanding what it meant. I knew the definition, but I couldn't explain why it mattered or what the practical implications were. That's shallow knowledge — and the Feynman Technique exposed it immediately.

The Surprising Part

The technique worked best for concepts I thought I already understood. For things I knew I didn't understand, I'd just write "I don't know this" and go study it. The real value was in exposing the shallow knowledge — the stuff I could recognize but not actually explain.

After doing this for all five concepts, my problem set performance improved noticeably. Not because I'd memorized more, but because I actually understood the underlying logic. When you understand why something works, you can reconstruct it even if you forget the exact steps.

How to Use It for Different Subjects

I've since used the Feynman Technique in other courses, and I've found it works differently depending on the subject:

For math and CS: Explain why the algorithm or proof works, not just what it does. The "why" is where the understanding lives.

For history and social sciences: Explain the causal chain. Why did X happen? What were the conditions that made it possible? What were the consequences?

For biology and chemistry: Explain the mechanism. Don't just say "the enzyme catalyzes the reaction" — explain how it does it, what changes, and why that matters.

For literature: Explain the argument you're making about the text. If you can't explain your interpretation in plain language, you probably don't have a clear argument yet.

What I'd Change

I'd start earlier. I did this the week before the midterm, which was helpful but rushed. If I'd done this after each lecture throughout the semester, I think I'd have caught the gaps much earlier.

Also — and this sounds weird — talking out loud worked better than writing for me. I ended up pacing around my room explaining things to myself, which my roommate found very strange. But it forced me to keep going even when I got stuck, whereas writing let me trail off with "...and then it just works."

If you try talking out loud and feel silly, try recording yourself. Knowing you're being recorded (even if you never listen to it) makes you more likely to complete the explanation rather than trailing off.

My Verdict

The Feynman Technique is genuinely useful, but it's not a quick study hack. It's a diagnostic tool. Use it to find out what you don't actually understand, then go fix those gaps. Don't use it as a replacement for actually learning the material first.

The best time to use it is after you've studied a topic and think you understand it. That's when the technique reveals the difference between thinking you understand something and actually understanding it.

Frequently Asked Questions

Q: Do I have to explain it to an actual person, or can I just write it down?

Either works. Writing it down is easier to do alone and lets you see the gaps more clearly (you can literally see where your explanation breaks down). Explaining out loud to a real person adds social pressure that some people find motivating. Try both and see what works for you.

Q: What if I genuinely don't understand the concept at all?

Then the Feynman Technique isn't the right tool yet. Go back to your notes, textbook, or a video explanation first. The technique is for checking and deepening understanding, not for initial learning.

Q: How long should a Feynman explanation take?

About 10–15 minutes per concept. If it's taking much longer, you're probably trying to explain too much at once. Focus on one specific concept or mechanism, not an entire chapter.

Q: Can I use the Feynman Technique for exam prep?

Absolutely — it's one of the best exam prep tools I've found. Go through each major concept on the exam and try to explain it simply. Any concept you can't explain clearly is a concept you need to review. This gives you a targeted study list rather than re-reading everything.