Inspired by Dr. James Tanton's Video, posted below, I asked my students to do a few experiments with pennies.

The first was to flip a penny twenty times and count the number of heads. The second was to flip three pennies twenty times, and record the number of heads for each trial. I am leading to Bernoulli trials, and I'll be using their data when we get there. The raw data can be found at this link. Using the probability calculated in the first experiment gives good predictions for the distribution in the second experiment. Our experiment shows that the probability of flipping heads with a penny is around 0.54.