ChanceMaker is a microworld programme developed by Dave Pratt and freely available to download.
It is designed to investigate the ideas that 11- and 12-year-olds have about chance. Children are presented with a series of gadgets, simulations of everyday random generators such as coins, spinners and dice. They are told that the gadgets are being programmed and asked which ones they consider not to be working properly. Later, they are challenged to mend the gadgets they consider not to be working.
Children do not necessarily recognise the importance of running a large number of trials to make such judgements. Neither do they always appreciate the significance of the role of the distribution, referred to here as the workings of the gadget.
Because feedback is available through the computer-based tools in many forms, and because the children are able to test out personal conjectures, they often begin to construct situated notions of the Law of Large Numbers and the connection between probability and data distributions.