Ekman Spiral

Everybody needs friends?

When we first began this experiment, our ability to reproduce the same results was very low. It appeared that something was going on close to the water's surface, and the refraction index of the water near the surface was obviously different. Before beginning the experiment, we stirred the water thoroughly, including the surface, but when we started the experiment, there stilled seemed to be something different about the surface. I was lost for words when asked "Where is the spiral?" by a student.

While thinking about this problem after finishing a day's experiments with students, a friend came to visit. "What is with the long face", he asked. He had nothing to do my area of research, but I explained the situation to him, and he replied saying, "Shouldn't you just remove the upper layer of water?" I muttered something about things not being quite that simple, but nevertheless tried floating some tissue paper on the surface of the water, removed it tried the experiment again. A beautiful spiral became immediately apparent.

And so following incantation was formed.

1. Remove surface water with tissue.
2. Start revolution immediately.
3. As soon as spinning up is complete (after about 3 mins.), immediately release the colored water.

Glycerin does not dry

Although we had worked out an incantation for the experiment, we still didn't know what was going on near the surface of the water. We thought at first that the water in glycerin solution was evaporating, and a "hard membrane" was forming over the surface, so we tried raising the room humidity with humidifiers, but it didn't have any effect. Looking for other causes, we discovered that glycerin is highly hygroscopic. It would appear that the water was not in fact evaporating, but rather the glycerin was drawing water in from the air. It wasn't a "hard membrane" that was being formed on the surface, but rather a soft membrane. Watery glycerin is light and has low viscosity, so it is very difficult to mix.

A picture is worth a thousand words

One day, a student who had just finished writing his thesis came and saw the video of this experiment.

Student: "What do you know, Ekman Spirals really do occur." 
Me:      "Hang on, if Ekman Spirals didn't occur, you wouldn't have been 
          able to write your thesis."
Student: "But I really thought that the Ekman spiral was only an armchair theory."
Me:      "So are you saying that your thesis is just an armchair theory?"