This is an interactive activity in which the randomness and probability of marbles being pulled out of a "bag" are calculated automatically and for trials up to 500. In short, you will be able to see how the experimental probability more accurately reflects the theoretical probability when larger numbers of trials are conducted (as compared to a few).
The Marble Mania screen has three main sections, one on the left side of the screen where you can choose the number of different colored marbles in the bag plus the number of marbles to draw and the number of trials to run. The right side of the screen has two sections. The top section graphically shows the number of times a certain color was picked (either as a bar or pie chart), while the bottom section depicts the frequency.
Marble Mania can be used as part of a lesson on uncertainty and probability. This interactive activity would work best as an enhancement to having students perform hands-on experiments where they either flip coins or pull marbles out of a bag a certain number of times and record their results. The usefulness of this online activity is that it can perform a high number of trials in a short period of time. So, it would be most useful to have students engage in the interactive as part of an assessment or after they already have performed a hands-on probability activity.