Probability is a number between 0 and 1 indicating how likely an event is to occur. 0 means impossible, 1 means certain.
For a fair coin, the probability of heads is 0.5 (50%). For an unfair or weighted coin, one outcome is more likely than the other.
As you increase the number of flips, the observed frequency (experimental probability) gets closer to the true probability. This is the Law of Large Numbers.
Try adjusting the coin's weight and observe how the results change over many flips!