Explainers, tutorials and "how it works"

One idea the viewer understands by the end (../story.md §1). The spine is one concrete example worked through, start to finish, not a tour of facts. Usually 30–90 s.

Ground it first

Start where the viewer already is: a person, a place or a situation they know, and a question they would ask about it ("why does the astronaut come home younger than her twin?"). The abstract device (a light clock, a graph, a field) enters inside that situation, as the thing that answers the question, and the film returns to the person at the end with the answer. A film that opens on the device alone is a diagram, not an explainer.

Devices that explain

• The object is the explanation. Build a thing whose working is the idea: a machine, a model, a map, a light clock, drawn so it reads as what it is (its material, its mount, where it sits in the scene). Every number on screen comes from it, and the camera tours through it: cutaways, an exploded view, a dive into the part that matters.
• One diagram that grows. Start from the simplest true picture and add one part per beat, each appearing when it is named; never a finished diagram dropped on screen at once.
• Continuous transformation. Each step morphs out of the last (a bar becomes an axis, a dot becomes a population), so the viewer never loses the thread to a cut.
• The worked example. One real input (a sentence, a number, a photo) travels through every step to the answer.

Shapes of information

Most explainable lines are one of a few shapes, and each has its own picture: a number that lands (data.md); a myth turned over (the wrong idea struck through, the right one printed over it); before and after; many things converging into a few groups; a network that densifies; one chosen out of many; steps in order; a real screenshot with the detail circled; a quote set as a poster; a chapter card. Pick the shape first, then the picture, so similar lines get different pictures and every line gets the one that shows it.

Words

• Narrated: the voice is the clock (../sound.md §2). Reveal each part when the voice names it, across the back half of the scene; keep a scene to about 19 spoken words (../film.md "Script and pacing").
• Not narrated: large lines carry it, up to about 10 words, each held 0.5 s + 0.3 s a word.
• Labels sit on the part they name, with a leader line when needed, and appear with it. No legends, no bullet slides.

Getting it right

• Every claim, value and step traces to the source; a number the source did not give is left out or marked illustrative. One data module drives every figure so the numbers agree with each other.
• Check the science or the logic of each step before animating it; a beautiful wrong diagram is worse than none.
• End on the one idea in one line. No brand end card unless asked.

Tells for this type

A slide of bullets; icons in circles; three cards in a row; the whole diagram at once; a narrator repeating the text on screen word for word.