Coin flip
Flip one to six coins on the big screen, with a running tally of heads and tails for lessons on chance.
How to use it
- Choose how many coins to flip, from one to six.
- Press Flip or the Space bar. The coin spins and lands on heads or tails.
- Watch the tally under the coins grow. Press R to clear it and start a new experiment.
Ideas for class
- Settle who goes first, with the class agreeing before the flip that the coin decides.
- Run a probability experiment: predict how many heads in twenty flips, flip twenty times, and compare.
- Flip two coins fifty times and tally HH, HT, TH and TT. Does each come up a quarter of the time?
- Teach the idea that a coin has no memory: after five heads in a row, is tails more likely on the next flip?
- Use heads and tails as a quick yes or no, an A or a B, or the two teams in a game.
- Compare a small sample with a large one: after ten flips the tally may be far from half, and after two hundred it settles.
Related
Questions
Is it a fair coin?
Yes. Heads and tails each have exactly the same chance on every flip, and each flip is independent of the one before. The result is drawn with your browser's secure random generator, then the coin animation shows it.
Why are my results not half and half?
Short runs of flips vary a lot. Ten flips can easily give seven heads. The share of heads moves closer to half as the number of flips grows, which is a key idea in probability.
Does the tally save?
No. It lasts as long as the page is open, and clears with the button, since it is meant for a quick experiment, not a record.
Can it flip several coins at once?
Yes, up to six. It shows each coin and adds them all to the tally, handy for questions such as how often all of three coins match.
Does the coin spin if my device reduces motion?
No. If your system is set to reduce motion, the result appears straight away.
Nothing you do here is sent to us. Names, lists and settings stay in this browser. No sign-in, no ads.