Archive for the ‘bubbles’ Category

Two new papers explore the complicated physics behind bubbles and foams

June 19th, 2019
Closeup photograph of bubbles floating through the air.

Enlarge / The complex physics of bubbles and foams have fascinated scientists for centuries. (credit: Ian Kington/AFP/Getty Images)

Human beings derive intense pleasure from bubbles and all kinds of foamy products, and scientists have long found them equally fascinating, given the complicated underlying physics. Most recently, a group of Japanese researchers published a paper in Scientific Reports describing two distinct mechanisms by which simple foams collapse. And in a new paper in the Proceedings of the National Academy of Sciences, physicists at MIT and Princeton University demonstrated how to develop spherical bubbles uniformly by confining them in a narrow tube.

Individual bubbles typically form a sphere, because that's the shape with the minimum surface area for any volume and hence is the most energy efficient. Back in the 19th century, Lord Kelvin proposed a bizarre soccer-ball shape called a tetrakaidecahedron (Greek for "fourteen faces" and sometimes translated "tetradecahedron"), with six square and eight hexagonal faces, to describe a bubble's natural geometry. It's known as "Lord Kelvin's cell," and while it was a valiant effort, that exact structure has yet to be observed in real-world bubbles, although physicists from Trinity College Dublin proposed a better solution to the conundrum in a 1993 paper.

Foams are ubiquitous in everyday life, found in foods (whipped cream), beverages (beer, cappuccino), shaving cream and hair-styling mousse, packing peanuts, building insulation, flame-retardant materials, and so forth. All foams are the result of air being beaten into a liquid formula that contains some kind of surfactant (active surface agent), usually fats or proteins in edible foams, or chemical additives in non-edible products. That surfactant strengthens the liquid film walls of the bubbles to keep them from collapsing.

Read 13 remaining paragraphs | Comments

Posted in bubbles, fluid dynamics, foams, Physics, science | Comments (0)

The secret to champagne’s universal appeal is the physics of bubbles

December 31st, 2018
Making champagne is fairly simple, but the physics behind its bubbly delights is surprisingly complex.

Enlarge / Making champagne is fairly simple, but the physics behind its bubbly delights is surprisingly complex. (credit: Jon Bucklel/EMPICS/PA/Getty Images)

It's New Year's Eve, and revelers around the globe will be breaking out the bubbly in massive quantities to usher in 2019. Why do humans love champagne and other fizzy beverages so much, when most animals turn up their noses when it's offered? Roberto Zenit, a physicist at Mexico's National Autonomous University of Mexico, and Javier Rodriguez-Rodriguez of the Carlos III University of Madrid in Spain, posit in the November issue of Physics Today that carbonation triggers the same pain receptors in our deep brains that are activated when we eat spicy food.

"This bubbly sensation you have when you drink a carbonated beverage basically triggers similar taste buds," said Zenit. "Champagne is just wine; what makes it special is the carbonation. It's a sad day when you drink flat champagne."

He and Rodriguez-Rodriguez study the behavior of various fluids (including paints), and carbonation is a particularly fascinating topic within that discipline. When the bubbles in champagne burst, they produce droplets that release aromatic compounds believed to enhance the flavor further. (When bubbles in a carbonated beverage like beer don't burst, the result is a nice thick head of foam.) And here's another interesting fact: the bubbles in champagne "ring" at specific resonant frequencies, depending on their size. So it's possible to "hear" the size distribution of bubbles as they rise to the surface in a glass of champagne.

Read 11 remaining paragraphs | Comments

Posted in 12 days of Christmas, bubbles, champagne, fluid dynamics, foam, Physics, science, Wine | Comments (0)