Coin flip
Heads or tails, big enough to settle an argument from the back of the room.
Heads or tails
Space flipR clear the tallyF full screenM sound
About a coin
- Sides
- 2
- Chance of each
- 50%
- Ten the same way
- 0.195%
- Exactly 50 of 100
- 7.96%
A coin has two sides and each of them comes up 50% of the time, which is the whole of it. Ten flips landing the same way is not impossible, only unlikely: 0.195%. And in a hundred flips, landing on exactly fifty heads is itself only 7.96% likely — fair does not mean even.
Good to know
Is the flip fair?
Yes, and in a stricter way than a real coin: the side is drawn from the browser’s cryptographic random source before the coin starts turning. A real coin is very slightly biased towards the side that was facing up; this one is not.
What is the tally for?
It counts the flips made on this device so it is possible to answer the question that always follows — “how many heads so far?”. It is kept in this browser only and the Clear button empties it.
Can the class see it from the back?
Press F, or the full-screen button, and the coin and the word fill the screen. The word is as large as the digits on the timer, which is what makes it readable from the last row.
Each one on its own page
Dice roller
One die or six, from d4 to d100, drawn as the solid it is.
Random number
A number out of any range, with no repeats if you want.
Random letter
A letter of the alphabet — all of them, or only vowels.
The rest of the kit
Name wheel
Spin to pick a pupil. Nobody is picked twice until everyone has had a turn.
Random groups
Split the class into even groups in one click, by number of groups or by size.
Classroom timer
A countdown the back row can read, with a bar that turns amber, then red.
Stopwatch
Start, lap, stop. Laps with splits, fastest and slowest marked.
Focus timer
Work and break rounds that run by themselves, 25 and 5 or your own.