The document discusses bubble sort, a simple sorting algorithm where each pair of adjacent elements is compared and swapped if out of order. It gets its name because elements "bubble" to their correct positions like bubbles rising in a glass of soda. The algorithm makes multiple passes through the list, swapping elements on each pass until the list is fully sorted. While simple to implement, bubble sort has a slow running time of O(n^2), making it inefficient for large data sets.