I rely heavily on PowerPoint presentations for math instruction and have discovered that, if done correctly, animated (GIF) images can greatly increase both interaction and learning. For example, a student activity involving rolling a pair of dice can be "accelerated" to show how an increase in sample size (n) will gradually approach a normal distribution. When rolling a pair of dice, 7 is the most likely combination while 2 and 12 will be the least likely.
After a small sample size of 5-10 rolls, the normalized pattern has yet to show. With 20-30 rolls, it may be seeming to take shape. Using an animated image to show the change as n increases to 100, 1000 or 10000 rolls (via simulation) can show how the curve gradually appears and comes into focus.
