All posts tagged: fluid dynamics

Mathematicians figured out the perfect espresso

Mathematicians figured out the perfect espresso

Published by Jenni Sidey

Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. People love a good cup of coffee, but how do you get a perfect brew? Barring philosophical deep dives into the nature of perfection, an international team of mathematicians and environmental scientists believe that it’s entirely possible to calculate the ideal espresso. Not only that, but they now have the formulas to back it up. The math detailed in their study published in the journal Royal Society Open Science is dense. But the short answer is that’s all about puck size. Picture the typical espresso machine at your favorite cafe. The small dish into which your friendly barista tamps coffee grounds is called the puck. After inserting it into the machine, hot water flows through the receptacle and molecularly absorbs the beans’ flavor, hue, and (most importantly) caffeine.  The quality of the final espresso depends on many aspects, including how the grounds are packed, how long water passes through the coffee, and the size of the grounds themselves. It’s …

The weird physics of plant-based milks is only just coming to light

The weird physics of plant-based milks is only just coming to light

Published by skeptic

Just a splash of the non-Newtonian, please Jack Andersen/Getty Images The physics of plant-based milks is strange. Researchers are only now beginning to understand it, and they hope that doing so could result in better beverages. Vivek Sharma at the University of Illinois Chicago and his colleagues found that most plant milks flow and drip in more complex and unusual ways than their animal counterparts. The team looked at eight different milks – cow, goat, pea, soy, oat, almond, coconut and rice – and studied their viscosity, or how difficult it is for them to flow. They found that all the plant-derived milks except for rice milk exhibited something called shear thinning, where the viscosity decreases with pressure. That means those milks are non-Newtonian liquids, physically more similar to ketchup or shampoo, which flow more easily when you apply pressure to the bottle than cow or goat milk, which have a constant viscosity. Sharma says this is because the plant milks contained very small amounts, often less than 0.1 per cent, of gums derived from …

Physicists calculate exactly how long that last drop takes

Physicists calculate exactly how long that last drop takes

Published by Jenni Sidey

Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. How much of your life is spent waiting for the last drops of syrup, olive oil, or even bodywash to drip from a container? This routine test of patience is owed entirely to complex fluid dynamics. But thanks to physicists at Brown University, people no longer have to guess how long it may take to finally empty that bottle of ketchup—provided you are well-versed in the right math. According to Jay Tang and Thomas Dutta, co-authors of a study recently published in Physics of Fluids, you specifically need to know about Navier-Stokes equations. These formulas use conservation of mass principles to describe how fluids move based on Newton’s second law of motion (force equals mass times acceleration). Tang typically focuses on the biophysics of bacteria, and how the organisms function and grow on wet surfaces. These relationships are much easier to study with everyday sources like kitchen liquids, however. Dutta recalled his grandmother always trying to force out the …