Understanding half-life using M&M's

Please note that M&M's are perfectly safe, and are not radioactive. M&M's can be used as a model of a sample of radioactive nuclei, however, because when they lie on a flat surface they can be in one of just two states - they can lie with the M up or with the M down. Let one of those states (M down, say) represent decayed nuclei.

With a package of M&M's, you can model a sample of decaying nuclei like this:

step 1 - count the number of M&M's you have.
step 2 - throw them onto a flat surface, and count the number of M&M's with M up. Remove all the M-down M&M's from the sample.
step 3 - repeat step 2 until you have no M&M's left.

Every time you throw the M&M's, you've gone through one more half-life. Here's the data from one trial:

# of throws 0 1 2 3 4 5 6 7

Trial 1 50 25 12 8 2 0 0 0

Predicted 50 25 12.5 6.25 3.12 1.56 0.78 0.39

# of throws	0	1	2	3	4	5	6	7
Trial 1	50	25	12	8	2	0	0	0
Predicted	50	25	12.5	6.25	3.12	1.56	0.78	0.39

The above is just a single trial; you should try it yourself to see what you get. This trial shows something interesting, however. When you have a large number of particles, they follow the predicted behavior very closely. When you only have a small number, the inherent randomness of the decay process is a little more obvious.