Wednesday 30 April 2025
The fascinating world of thin liquid films has long been a subject of interest for scientists, and researchers at Cornell University have recently shed new light on a phenomenon that’s both beautiful and intriguing: the fringe pattern around a beet slice.
When you place a slice of beet in a thin layer of its own juice, you’re likely to notice a distinct border surrounding it – a phenomenon that’s been observed by many but poorly understood until now. The researchers’ study reveals that this fringe pattern is not caused by the absorption of coloring matter or deformation of the liquid surface, as previously thought.
Instead, they discovered that the rise of the contact line on the side wall of the beet is responsible for creating a suction effect, which in turn generates the fringe pattern. This phenomenon occurs when the liquid film’s thickness is below a certain threshold, allowing the capillary rise to dominate and create a dimple or depression on the surface.
The researchers used a motorized confocal displacement sensor to measure the temporal evolution of the liquid surface profile across the fringe, providing a detailed understanding of the process. They also developed a scaling analysis that accurately estimates the dependence of the dimple’s lifetime on the liquid properties and film thickness.
One of the most striking aspects of this research is the way it highlights the importance of considering both surface tension and gravity when studying thin films. While surface tension tends to smooth out the dimple, viscous drag acts against it if the film is sufficiently thin. The researchers’ findings also demonstrate that the fringe pattern can last for a longer time than expected, as the flow velocity near the beet slice decays rapidly over time.
The study’s implications are far-reaching, with potential applications in various fields such as materials science, biology, and even art. For instance, understanding how to manipulate the friction between surfaces could lead to new developments in materials engineering or robotics.
Furthermore, this research provides a fascinating example of the complex interplay between surface tension, gravity, and viscous drag that governs the behavior of thin films. By shedding light on this phenomenon, scientists can gain a better understanding of the intricate mechanisms at play and potentially uncover new insights into other related phenomena.
The researchers’ use of advanced measurement techniques and theoretical modeling to explain their findings is a testament to the power of interdisciplinary research in advancing our knowledge of the physical world. As we continue to explore the intricacies of thin films, it’s likely that we’ll uncover even more surprising and beautiful examples of the complex interactions that govern our universe.
Cite this article: “The Fringe Pattern Enigma: Unraveling the Mystery of Beet Slices and Thin Liquid Films”, The Science Archive, 2025.
Thin Films, Liquid Surfaces, Contact Lines, Capillary Rise, Dimples, Fringe Patterns, Surface Tension, Gravity, Viscous Drag, Materials Science
