The Bubble Sort is a simple algorithm for ordering the values within an array. However, while it maybe simple, it is not as efficent as other algorithms unless the array it is being applies to meets specific conditions.
Here are the steps the algorithm takes:
The number of passes required increase significantly with the number of items in the array. If the values are in reverse order (which is the worse case scenario) it would take n^2 comparisons. If you had 10 values in reverse order it would take 100 comparisons.