Purpose:Demonstrate that an ordered state is statistically possible.
Place two balls of each of two different colors in the diffusion apparatus. To start, either place all four one the same side of the apparatus; or place two of one color on one side of the apparatus, and two balls of another color on the other side. Start the machine going with the hole between sides open.
• Encourage students to notice that although statistically it is less probable, the arrangement of both orange balls on one side and both green balls on the other side will happen occasionally.
• Ask: Is this as likely to happen using three balls of each color? With four?
This is essentially showing the exception to the general principle of demonstration I6-21. With a small enough number of balls in the model, it is statistically possible to “reverse entropy” to a limited extent – that is, occasionally, the balls will randomly organize themselves so that they are once again sorted by color.