Borrow a structure. Say where it breaks.

STEP 1 OF 6 · INTRODUCE THE TARGET The idea to teach

This page teaches one analogy, in the six steps of Shawn Glynn's Teaching-With-Analogies model. Each section is one step, in order. The idea you want to teach is called the target. Here it's a simple electric circuit: a battery, a loop of wire and a bulb.

Two words matter. Current is how much electric charge passes one point each second, measured in amps. Voltage is the push that drives it, measured in volts. The trouble is that you can't see either one. Nothing in the wire looks like it's moving.

STEP 2 OF 6 · RECALL THE ANALOG Something they already know

So borrow something your reader can picture. The borrowed idea is called the analog. Here it's water: a pump pushes water around a closed loop of pipe, and one section of the pipe is narrow.

Pick an analog your reader really knows. An analogy built on something they've never seen explains nothing. Ask them to picture it before you go on.

STEP 3 OF 6 · IDENTIFY THE FEATURES The parts on both sides

List the parts that matter on each side, before you connect anything:

Leave out what doesn't matter. The color of the pipe and the brand of the battery aren't features of this analogy.

STEP 4 OF 6 · MAP THE SIMILARITIES Link each part to its match

Now draw the links, one pair at a time, and say why each pair matches:

Map carefully, even where the analogy holds. Keith Taber describes a student who was taught a water analogy and concluded that a resistor slows the current only at the resistor, after which it flows freely again. Both water and charge in a single loop slow down everywhere at once. The analogy was right. The mapping was left to the student.

STEP 5 OF 6 · SAY WHERE IT BREAKS DOWN Where the analogy stops being true

Every analogy breaks somewhere. This is the step most explanations skip. In a study of four high school physics textbooks, Dundar Yener found 50 analogies, and only 6% of them said where they stopped working. The other 94% left it to the reader.

Here are three places where water in pipes stops matching an electric circuit, in the same format as the map above:

Say each break out loud, as part of the lesson. If you don't, the learner fills the gap with the analog, and the analog is wrong there.

STEP 6 OF 6 · DRAW CONCLUSIONS What it's good for, and where to stop

Finish by saying what the analogy explains and where to drop it:

That's the whole model: introduce the target, recall the analog, identify the features, map the similarities, say where the analogy breaks down, and draw conclusions.

This isn't swapping hard words for easy ones, like the Feynman and ELI5 lessons, or starting concrete, like the 3Blue1Brown lesson. It borrows a whole structure from something familiar, and says where the borrowing stops.

Watch it in 44 seconds

The clip runs the same analogy through all six steps. Watch the step tag in the top right corner, and what happens when the pipe and the wire are cut.

This page, step by step

This page is built as the model: one analogy, six steps, in order. It checks itself each time it's built:

Teach this way

1. Introduce the target. Name the idea you want to teach, and say what makes it hard to picture.
2. Recall the analog. Pick something your reader knows well. Ask them to picture it.
3. Identify the features. List the parts that matter on each side. Leave out the rest.
4. Map the similarities. Link the parts one pair at a time, and say why each pair matches.
5. Say where it breaks down. Find at least three places where the analog would give a wrong answer. Say each one, and the wrong idea it would lead to.
6. Draw conclusions. Say what the analogy is good for, and when to drop it.
7. Test it. Ask a question the analogy gets wrong. If your reader answers it right, step 5 worked.

Ask your agent

Explain the concept below with one analogy, using Shawn Glynn's Teaching-With-Analogies model. Do the six steps in order, and label each one.
1. Introduce the target: say what the concept is and what makes it hard to picture.
2. Recall the analog: pick one familiar thing the reader is likely to know. Say who it would not work for.
3. Identify the features: list the parts that matter on each side.
4. Map the similarities: give each link as a pair, with one sentence on why it matches.
5. Say where your own analogy breaks down: list at least three places where reasoning from the analog gives a wrong answer about the concept. For each one, say the wrong belief it would cause.
6. Draw conclusions: say what the analogy is good for and when to stop using it.
Finish with one question that the analogy would answer wrongly, and the right answer.

Concept:
[paste here]

What good output looks like: a step 5 as long as step 4, and a final question that would catch someone who trusted the analogy too far.