Interactive explainers
Playful pages that explain size, scale and numbers by letting you explore. 2 resources; API, key, license and embedding quoted from each site's own pages, checked Oct 23, 2026.
neal.fun
Each piece turns a big idea, like scale, money or time, into something you can click through in a few minutes.
License unclear
The Scale of the Universe 2
One scroll takes you from the smallest particles to the size of the observable universe, and the jumps between neighbours make sizes finally feel real.
License unclear
Side by side
| Resource | API | Key | Data download | Commercial use | Embed |
|---|---|---|---|---|---|
| neal.fun A collection of small browser games and interactive explainers. |
API unclear | — | — | Commercial use unclear | Embedding unclear |
| The Scale of the Universe 2 A browser zoom tool that lines up objects from the subatomic to the whole observable universe so you can scroll between size scales and click objects for short notes. |
API unclear | — | — | Commercial use unclear | Embedding unclear |