At what angle does a bubble move most swiftly through a tube of liquid? Horizontal? Vertical? Something in between? The students found that angles of 45-60 degrees produced the fastest bubbles.
Then we sought to determine if the speed of the bubble is constant from start to finish. The results of all the teams of students were combined to produce the chart below. The plots of distance versus time resulted in straight lines i.e. the speed of the bubble was constant.