Bubble chart is a kind of mind map, which is composed of big circle in the center and small circle around, connected by straight line. The center is the object being described, and the surroundings are the features of the object. A bubble chart is composed of many bubbles. The bubble in the middle is the central theme. The bubble branches around the central theme to describe the details of a thing clearly. A bubble chart is a chart that shows the correlation between variables. Similar to a scatter plot.