JAN 01, 2020 12:00 PM PST

Century-old Bretherton's Bubble Problem Solved

(Pixabay)

Some of the most common phenomena in life also hide puzzling mysteries. 

When you pour water into a glass, many air bubbles would often appear. Because of their lower-than-water density, they rise to the top without any doubt. But the same thing does not happen to the air bubbles in a closed capillary tube with water: they get stuck at where they first occur. 

This simple yet perplexing problem first captivated scientists a century ago. In a recent publication, a bachelor student and his laboratory supervisor at the Swiss Federal Institute of Technology Lausanne (ÉPFL) reported that they found a proper solution to address the century-old mystery.

For the portion of air that cannot be dissolved, it forms bubbles in liquids. Once the bubbles reach the surface, they pop, releasing the gas back to the atmosphere. Gas bubbles can be seen almost everywhere in life: carbon dioxide soaring in carbonated beverages, water vapor released in boiling water, and air freed from agitated water.

On Earth, air bubbles in water should always flow upward unless encountering resistance. In microgravity environments like space, however, they do not follow the same rule.

Bubbles in water in space (Canadian Space Agency)

In his 1961 paper, Francis Patton Bretherton, an applied mathematician, developed an equation that models the bubbles' shape to solve the problem. Since then, the phenomenon was given the name "Bretherton's Bubble Problem". 

According to the latest study, the bubbles in the capillary don't get stuck. Instead, the observation made by the Swiss team proved that they are actually rising upwards, but just in a languid pace. 

Using an optical interference microscopy, they discovered that there's a liquid film about nanometes (10^-9 meter) thick between the bubbles and the wall, resulted from the geometry of the tube and the hydrodynamics. The film exerted a force of resistance to the bubbles, which slowed down their upward movement.

The researchers believed that their findings would be helpful to dissect other phenomena in fluid mechanics at the nanometric scale, especially when it comes to biological entities.

The exceptional contribution to this discovery by the bachelor student Wassim Dhaouadi earned him praises and recognitions. As a research assistant to ÉPFL physics professor John Kolinski, Dhaouadi was described as diligent and driven. "He essentially participated out of his interest in the research, and wound up publishing a paper from his work that brings to rest a centuries-old puzzle," Kolinski commented on his mentee in a press release.

This study is published in the journal Physical Review Fluids.

Source: Phys.org

About the Author
  • Graduated with a bachelor degree in Pharmaceutical Science and a master degree in neuropharmacology, Daniel is a radiopharmaceutical and radiobiology expert based in Ottawa, Canada. With years of experience in biomedical R&D, Daniel is very into writing. He is constantly fascinated by what's happening in the world of science. He hopes to capture the public's interest and promote scientific literacy with his trending news articles. The recurring topics in his Chemistry & Physics trending news section include alternative energy, material science, theoretical physics, medical imaging, and green chemistry.
You May Also Like
OCT 22, 2019
Space & Astronomy
OCT 22, 2019
Here's What We Know So Far About Titan's Liquid Methane Oceans
Titan is perhaps one of the most captivating moons orbiting Saturn today; so much so that astronomers spent a lot of time studying it when the Cassini miss...
OCT 29, 2019
Chemistry & Physics
OCT 29, 2019
Protein Batteries - Talk About "Power Bars"
The pioneers behind lithium-ion (Li-ion) batteries were awarded Nobel prize this year. Still, scientists around the world already wish to move beyond this...
DEC 01, 2019
Space & Astronomy
DEC 01, 2019
Jupiter's Great Red Spot May Not Be Dying After All
Most people recognize Jupiter as the largest known planet in our solar system, but there’s another eccentric quality about the planet that helps it s...
DEC 11, 2019
Chemistry & Physics
DEC 11, 2019
Physics in Peril? (Part I)
If you haven't picked up from popular science news outlets, you probably have heard of a thing or two about a troublesome notion from the acclaimed The...
JAN 05, 2020
Space & Astronomy
JAN 05, 2020
Is Betelgeuse on the Verge of Going Supernova?
There’s been a lot of discussion happening as of late with respect to the Orion constellation’s red supergiant star Betelgeuse. Being one of th...
JAN 13, 2020
Space & Astronomy
JAN 13, 2020
Lunar Dust is Actually Quite Dangerous to Humans
Most people have a tendency to think that lunar dust isn’t any different than the dirt found here on Earth, but quite the opposite is true. In fact,...
Loading Comments...