The bubble sort works by comparing each item in the list with the item next to it, and swapping them if required. The algorithm repeats this process until it makes a pass all the way through the list without swapping any items (in other words, all items are in the correct order). This causes larger values to "bubble" to the end of the list while smaller values "sink" towards the beginning of the list.
Simu-bubble is an interactive exercise designed to help you to understand how a bubble sort works. The computer presents a list of random order to you, and ask you to sort it step by step, until the required order, according to the bubble sort.