Name Wheel

A wheel on the board changes who answers. Hands-up questioning hears from the same four students all lesson; a wheel spreads the questions across the room, and — just as usefully — it takes the choice off the teacher, so nobody reads a motive into being picked.

Turn on Remove the winner automatically and the wheel works through the class without repeats: each spin draws from the names that are left, so everyone has been heard once before anyone is asked twice. Reset the list at the start of the next lesson.

• Who answers the next question, reads next, or comes to the board.
• The order of presentations, so nobody argues about going last.
• Classroom jobs and rotas for the week.
• Which group starts, and which table tidies up.
• Pairing: spin twice, put the two names together, spin again.

For a draw in front of the people in it, a wheel is about as fair as a hat and much harder to fumble: every entry gets an identical slice, the wheel cannot be nudged by dragging it, and the result is visible to everyone at the same moment.

Be honest about what it cannot do. Nobody watching a recording afterwards can confirm that the list on screen was the full list of entries, or that the spin was the first one. If the prize is worth arguing over, show the whole list on screen before spinning, spin once, live or on camera, and let the entrants see the wheel rather than a screenshot of the result.

If someone should have two chances — a raffle where they bought two tickets — put their name in twice. Two slices is exactly double the chance, and everyone can see it on the wheel.

When you press Spin, the page asks the browser for a random number from crypto.getRandomValues, the generator used for cryptographic keys and seeded by the operating system. The number is mapped to a name by rejection sampling: draws that would fall into an incomplete final block are thrown away and redrawn, so with 7 or 30 or 53 names every one of them is exactly as likely as the others. Plain arithmetic without that step quietly favours the first few names.

Only then does the wheel start moving. The animation runs to the slice that was already chosen, which is why the length of the spin, the speed of your finger and where the wheel stopped last time change nothing about the result. Dragging the wheel is switched off for the same reason.

Your list stays in this browser. It is saved in local storage on this device so it is still there tomorrow, and it is never uploaded, so nobody else — including us — can read the names.

• Short labels win. First names, or a first name and an initial; the labels are cut at 22 characters so one long entry cannot shrink the whole wheel.
• Up to about 50 names stay comfortably readable on a classroom screen. The wheel accepts up to 200, but past 50 the slices get thin and the winner is easier to read in the pop-up than on the wheel.
• Blank lines and stray spaces are ignored, so pasting a column out of a spreadsheet works as it is.
• Shuffle before a public draw: it changes who is next to whom, so nobody can claim they knew where the pointer would land.
• A slower spin (8 seconds) is for an audience; 3 seconds is for running through a class quickly.
• Duplicate names are allowed on purpose — each copy is a separate slice and a separate chance.