Air speed more important than soap film thickness, study finds
There’s a science behind the art of blowing soap bubbles.
It’s not the thickness of the soapy film but rather the speed of the blowing gust of air that determines whether bubbles will emerge, scientists in France report in the Feb. 19 Physical Review Letters.
“We have all blown soap bubbles,” says study coauthor Laurent Courbin, a physicist at the University of Rennes in France. “It’s nice to be able to explain simple experiments that we have all experienced in our lives.”
Courbin and his colleagues looked through centuries of studies, but they couldn’t find any explanation of the physics behind bubble blowing. So the team built a device that pumps a controlled, uniform layer of bubble liquid over a roughly 1-meter-high opening of adjustable width. The scientists peppered this large,