Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Guiding Particles with Chladni Patterns
During the 19th century, Ernst Chladni and Michael Faraday independently explored the patterns formed by particles of different sizes placed on a vibrating plate. Faraday found that large particles accumulated at nodes of the plate, where there was no vertical vibration, whereas smaller particles moved toward anti-nodes, where air currents caused by the large vibration…
Giving Chocolate that Smooth Finish
Anyone who’s tried to make chocolate confections at home can tell you that achieving that perfect smooth consistency isn’t easy. It was only after Rodolphe Lindt invented the process of conching in 1879 that anyone enjoyed smooth chocolate. Conching is what allows granular solids like sugar, milk and cocoa powders to mix with liquid cocoa…
Reader Question: Inside a Vortex
Reader embersofkymillo asks: Hey FYFD, could you do some analysis/explanations behind the physics of this vortex stuff? I love when you do spots on Slow Mo Guys vids and figured I’d share a recent one w you I enjoy doing that, too! So let’s talk a little about vortices. What Dan’s tea stirrer is doing…
The Leidenfrost Crack
In 1756, Leidenfrost reported on the peculiar behaviors of droplets on surface much hotter than the liquid’s boiling point. Such droplets were highly mobile, surfing on a thin layer of their own vapor and were prone to loud cracking noises. More recently, scientists have observed that drops with an initially small radius eventually rocket off…
Drinking Coffee in Space
You probably don’t give much thought to the forces involved in drinking here on Earth. That’s because gravity’s effects dominate over everything else. Our cups are designed to hold a liquid until we use gravity to pour it into our mouths. But that technique doesn’t work in microgravity. There other forces govern how liquids flow:…
Wrapping Rivulets
Tea lovers have long been frustrated by the tendency of liquid jets to adhere to solid surfaces – the so-called teapot effect that makes the last vestiges of every pour drip down the spout. By investigating the effect with vertical rods, researchers found that, at low enough flow rates, a liquid jet is able to…
Inside an Evaporating Drop
The evaporation of a simple droplet holds far more complexity than one would expect. If you look closely at the edge of the drop, there’s a tiny, beautiful display at work. It begins with small variations in surface tension at the contact line where solid, liquid, and gas meet. These could be caused by local…
How Rain Can Spread Pathogens
Rainfall can help spread pathogens from an infected plant to healthy ones. This transfer can happen both through droplets and by dry-dispersal of pathogen spores (top). When a raindrop hits a leaf, its initial spread triggers a vortex ring of air that can lift thousands of dry spores into a swirling trajectory (bottom). That boost…
Fighting Resonance
Resonance is a funny creature, as Dianna discovered when she tried to sing a rising scale through a tube. At certain notes, everyone who attempted to do it had their voices crack. Tracking down the source of the mystery means digging into what exactly resonance is and what the differences are between driving a system…
Plant Week: Bunchberry Dogwood
The bunchberry dogwood, unlike its taller relatives, is a low-lying subshrub that spreads along the ground. But it sports some of the fastest action of any plant, requiring 10,000 frames per second to capture! When young buds form in the bunchberry flower, their four petals are fused, completely hiding the stamens. As the plant matures,…