Count equal sectors
The chance of a color is its sector count divided by the total sector count.
Probability Spinner
Configure equal spinner sectors, run seeded trials, and compare observed counts with theoretical chances.
Grades 3–5 · Statistics
Your goal
Give red 2 equal sectors, blue and yellow one each, then collect at least 10 trials. Compare experimental counts with the theoretical chances.
Reduced motion is on. The controls still update the scene.
0 trials. Red 0, blue 0, yellow 0. Red theoretical chance is 1/3. Latest result none yet.
The spinner uses a repeatable seeded pseudorandom generator with sector area proportional to chance. Samples are never forced to equal expected counts. Changing the seed or number of red sectors starts a new experiment. There is no physical spinning animation or automatic playback.
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Learn with Probability Spinner
Probability Spinner lets elementary students compare a chance model with the results of repeated trials. Children change the number of red sectors while blue and yellow keep one equal sector each, then collect individual spins or batches of ten. Colored frequency bars show observed proportions beside markers for theoretical probabilities. A shareable experiment seed reproduces the same trial sequence, and changing it creates a different experiment. The results can vary substantially in small samples because counts are generated from individual trials rather than forced to match the expected proportions.
What to look for
Compare experiments
Change the seed and repeat an experiment to see different sample results.
Collect more trials
Larger samples often settle closer to the theoretical fractions, but exact agreement is not guaranteed.
For teachers and curious learners
Compare theoretical outcome probabilities with variable experimental frequencies. Ask students to predict what will happen, change one setting, and explain what they observe. Learn gives a starting point. Practice and Challenge offer new goals with the same scene.
The spinner uses a repeatable seeded pseudorandom generator with sector area proportional to chance. Samples are never forced to equal expected counts. Changing the seed or number of red sectors starts a new experiment. There is no physical spinning animation or automatic playback.