The Explanation LabAll 20 lessons

10 WORDS · Language people can use

Fewer prerequisites, same truth.

You will learn how to make an explanation simpler without making it wrong, and a quick test to tell the difference. It takes 3 minutes.

Why is the sky blue?

Here's how an expert answers.

The expert answer

Rayleigh scattering by N₂ and O₂ molecules scales with λ⁻⁴, so diffuse skylight is dominated by short wavelengths.

assumed concepts6real cause kept: yes

It's correct. But to follow it, you need to know six things first: what scattering is, what N₂ and O₂ are, what λ means, what "to the minus four" does, what a wavelength is, and what diffuse skylight is.

Watch the clip

The clip tries two ways to make that answer simpler. One works. One doesn't.

30 seconds · lesson 10 of 20 from the full video

The name for it

THE NAME FOR IT

ELI5: Explain Like I'm Five

From the online forum r/explainlikeimfive

Done right, ELI5 cuts the number of concepts you must already know. It keeps the real cause intact.

The easy mistake

Not ELI5: just wrong

The sky is blue because it reflects the ocean.

assumed concepts0real cause kept: no

Cute. Wrong. And it can't explain anything else.

This is what people often think ELI5 means: say something short and cute. But a wrong answer isn't a simple version of the right one. It's a different answer.

The real thing

Keep the cause. Remove what the reader has to know in advance.

Fewer prerequisites

Sunlight is a mix of colors. Air molecules scatter short blue waves far more than long red ones. So blue reaches you from all over the sky.

assumed concepts3real cause kept: yes

Fewer still

Sunlight is every color mixed together. Air bounces blue light around much more than red. So wherever you look up, blue is bouncing toward you.

assumed concepts1real cause kept: yes

Look at the meters. The number of things you need to know drops from six to one. The real cause (air bounces blue light more than red) is still there in every version.

Test it

A real cause keeps working on new questions. A made-up one doesn't. So try this. Using only the last answer above, why are sunsets red?

Think about it before you open the answer.

Show the answer

At sunset, light crosses far more air to reach you. Most of the blue gets bounced away on the trip. Red is what's left.

Same cause, new question, and it still works. Now try the ocean story on sunsets. It has nothing to say.

TAKEAWAY

Remove prerequisites.
Never remove the truth.

Write your own

  1. Write the expert answer first.
  2. List what a reader must already know to follow it.
  3. Explain or remove items from that list, one at a time. Keep the cause.
  4. Test it: use your simple answer to predict something new. If it can't, you cut too much.

Ask your agent

"Explain like I'm five" often gets you the cute, wrong version. Ask for fewer prerequisites instead:

PROMPT
Explain the topic below so that someone with no background can follow it.
Rules:
- Keep the real cause or mechanism. Never swap it for a story that's easier but false.
- Before you write, list the concepts the expert explanation assumes. Then reduce that list to one or two.
- Use everyday words and one concrete example.
- End with one new question your explanation can also answer, and answer it with the same cause.

Topic:
[paste here]

What good output looks like: a short explanation that still names the real cause, plus a second question it answers without new ideas.

Sources