VerbSnap
A tiny game about how we say what proteins do. It is easy — and wrong — to write that a protein wants, hunts, decides or walks. Real molecules only jitter, bump, and stick when a shape fits. Each round shows a claim; call it Mechanism (honest physics) or Purpose (teleology). There is no clock: take your time. Nothing is installed; nothing about you is collected.
This is the tool — a free learning game with no login and nothing tracked. The claim bank is shown in full in the guide below, which works with or without JavaScript. The point isn’t to score high. Purpose talk is the easy default, and in adults it creeps back when they must answer fast (a real, documented effect), so this game gives you time to read every word.
Loading the game… If it does not start, the full claim guide below still works.
How to play. Press Start. A claim about a protein appears above the bins. Read it, then decide whether it is written as honest Mechanism or as Purpose (teleology) and choose — tap a bin, click a button, or press 1/M for Mechanism, 2/P for Purpose. There is no way to lose: a purpose claim reveals its flagged words and its honest rewrite. Press Next (or N) when you are ready. The two ways of writing each fact are about the same length, so you have to read the words.
The no-intent verb lint
Fold Commons writes protein stories under a verb lint: a short list of intent-words that are banned because they smuggle in a goal a molecule cannot have. A protein does not want, try or decide; it is jostled, and sometimes a shape fits and sticks. The site keeps ONE such list and every page is checked against it; these are the words from it that the claims below use:
searcheshateshuntswalksdecidestriesknowsgoes towantsin order tolearnssacrifices
The game also flags a short teaching list of force, motion and need words
(not part of the site’s lint, because chemists use some of them as shorthand): words like
help, locks, picks up, needs, pulling, guards, wrong, breaks, worked out, gets tired. Said of a molecule with no
mechanism beside them, they read as a goal.
A claim is Purpose if it uses one of these (or any other intent framing); it is Mechanism if it describes only what the molecules do — jitter, bumps, shapes that fit, concentrations that fill and empty. “Recognises” and “its job is to” are allowed only when the very next clause gives the mechanism.
The claim bank
Every claim in the game is one biological fact written two ways. The Purpose column trips the verb lint (the banned verbs are marked); the Mechanism column is the honest rewrite the game rewards.
Answer key — open it after you play
| Topic | Purpose (flagged) | Mechanism (honest rewrite) |
|---|---|---|
| Enzyme meets substrate | Picky searches the whole crowded cell, all day long, for the one molecule that she can help. flagged: searches, help | Picky is bumped into thousands of times. Most bumps do nothing. When a shape fits, it sticks. |
| Hydrophobic core | Shy Core runs off and hides deep inside the protein, because it hates the cold water all around it so much. flagged: hates | Shy Core ends up inside: water stays stuck to water, and the oily parts end up where the water isn’t. |
| Antibody | The antibody hunts the germ down and locks it up so it cannot hurt anyone. flagged: hunts, locks | The antibody drifts until it bumps a shape that fits its tips. Then it sticks. |
| Oxygen carrier | Hemoglobin picks up oxygen in the lungs because the body needs it down in every busy muscle. flagged: picks up, needs | Where oxygen is plentiful, hemoglobin’s pockets fill. Where it is scarce, the oxygen lets go. |
| Molecular motor | Myosin walks along the actin cable, pulling the muscle tight so that you can move your arm. flagged: walks, pulling | Myosin is jostled constantly. ATP makes backward steps less likely, so on average it moves along. |
| Channel / gate | Gate guards the cell wall and decides who gets in. flagged: decides, guards | Gate lets water through because only water fits the door. |
| Mutation | One wrong letter in the gene’s recipe always breaks the whole protein, so it can never work again. flagged: wrong, breaks | One changed letter can change the fold. Sometimes nothing happens; sometimes the shape can’t do its job any more. |
| AlphaFold prediction | AlphaFold worked out the true shape of this protein, so it is settled for good. flagged: worked out | AlphaFold made a very good guess at this shape. An experiment can check that guess. |
| Chaperone folding | The chaperone tries hard to fix the tangled protein, and if it fails, it decides to destroy it for good. flagged: tries, decides | The chaperone’s pocket opens and closes as ATP binds and lets go. A floppy chain gets more chances to settle. |
| Signalling receptor | The receptor knows its own hormone and goes to meet it at the surface of the cell. flagged: knows, goes to | Hormone molecules drift past. When one fits the receptor’s pocket it sticks, and the receptor changes shape. |
| Cargo transport | Kinesin wants to deliver its cargo, so in order to reach the far end of the track it never gets tired. flagged: wants, in order to, gets tired | Kinesin is jostled at every moment. Each ATP makes a forward step a little more likely than a backward one. |
| Adaptive immunity | The T cell learns what the virus looks like and then sacrifices itself to protect the whole body. flagged: learns, sacrifices | Of many T cells, the few whose surface shape happens to fit a viral piece stick and copy themselves. |
Methods & about
This is a teaching game, and it is honest about being a simplification. The “Purpose vs Mechanism” line is not always sharp — some words (“recognises”, “its job is to”) are fine when the mechanism follows immediately. The game uses the strict reading: if an intent verb stands alone, it is Purpose. The claims are authored from the Fold-Commons narrative-method bible (§5.1 no-intent law and §5.2 do/don’t pairs); the misconception it targets — promiscuous teleology, which returns in adults under time pressure — is from Kelemen & Rosset (2009). Children lean on purpose talk by default, so the game has no clock. Every claim is written by hand, not generated. The game keeps no score history, uses no accounts, and sends nothing anywhere.
Want the deeper, native experience? See the Fold Commons apps. Everything we make is free and non-profit; learn more on the home page.