William thompson, better known as Lord Kelvin, was a great scientist, known for his contributions to the fields of thermodynamics and electricity. Although, above all, to name a scale used to measure temperature. He contributed very important works to science. However, even the brightest minds are wrong. And apparently he did so by proposing the existence of a shape that should rotate naturally when falling into a fluid. Scientists of the time took the Kelvin theory as good, without stopping too long to check it. Let’s see, who was going to question the claims of such an illustrious physicist?
They had to pass 150 years so that, finally, someone has tried to prove it. Those responsible for doing so have been researchers from United States and Sweden, the results of which can be read in a study recently published in Physical Review Fluids.
To carry out their research they have followed the instructions of Lord Kelvin, as one who follows the recipe of the most illustrious of chefs. But the result, unfortunately, has not been the plate what did you expect.
The mistake behind Kelvin’s theory
Kelvin’s theory deals with a figure that he baptized as isotropic helicoid. He left the instructions for building it, so these scientists used them to print five 3D models.
Basically, it consists of a sphere with fins placed at 90º and 45º angles, so that it can be seen same from any angle. Basically, that’s why it’s isotropic.
The lord also described how it should behave when falling into a fluid. Supposedly, I should first start to turn and then, as it sank, pick up speed. They did so with five models of different sizes, but in no case did they support Kelvin’s theory. The figures were sinking. No more.
This is surprising, since the scientist’s manuscripts describe step by step how to build the figure. Even the materials. This, as explained by one of the authors in statements to Live Science, suggests that he did not just theorize. He also built a model. How could you move on if it didn’t work out?
Initially these scientists of the present thought that it could be precisely the reason why no one ever reproduced the experiment. Maybe they did; but, when failing, they abandoned their endeavor.
There is still hope
But perhaps all is not lost. There is something about which Kelvin’s theory can be correct.
In search of an explanation for what the physicist said in his day, they decided to analyze how the liquid flowed, specifically silicone oil, through the helicoids.
They saw that there was something in which Kelvin’s theory was true: a relationship between the motion of the helix through the fluid and its rotation. And it is that, as the figure sinks, the friction of oil particlesGuided from one fin to the next, they should generate a force to make it rotate. And, the lower, the faster. The problem is that the effect was miniscule.
Therefore, it could be that Kelvin’s theory was perfect on paper, but with an exaggeration in the force that could have such an effect. Even so, these scientists believe that, with some modifications in the manufacturing, perhaps they could be able to turn the helicoids.
Maybe he wasn’t so wrong after all. But even if they definitively proved that he was, many other of his theories and works will still be of great importance to physics. Nobody is perfect. Lord Kelvin was not either.