By Ted Kinsman

Many times a research paper will be published that will show a unique scientific experiment. I was reading a technical paper on fluid flow where the research was done with one color light to measure the thickness of the soap film for flow analysis. I modified the experimental setup to use white light, thus showing different thickness of a soap film as different colors. This image is a still from a video series showing fluid flow. The soap flows out of a reservoir between vertical wires that are pulled apart so that the resulting soap film shows optical interference. These images have appeared in numerous books, but the movie was used by the cartoon television show “South Park” to represent hallucinations by the central characters. My physics students thought is was just grand. I have used this thin soap apparatus to show golf ball lift and drag, as well as eddy currents.