This activity uses coin-flipping to demonstrate the time-evolution of entropy. Use it in conjunction with random.org's random integer generator.
Generate 80 random integers to dictate which coins to turn over at each time interval. Then, click on the corresponding coin on this page to turn it over. Over 80 trials, you can track the macrostate (number of "heads up" coins) of the system over time.
A heads-up coin is shown as not filled-in (white background). A tails-up coin is showed as filled-in (black background).