Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
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Superman’s Hair Gel
I love a good tongue-in-cheek physical analysis of superheroes. This estimate of the drag force experienced by Superman’s hair when outracing a plane or speeding bullet was done by Cornell students. According to their calculations, Superman’s hair (or his hair gel) must withstand nearly 80,000 Newtons of force. That’s a bit less than the typical…
A Dance of Hydrogen Bubbles
Hydrogen bubbles rise off zinc submerged in hydrocholoric acid in this short film from the Beauty of Science team. In high-speed video, the rise of the bubbles is stately and mesmerizing. Notice how the smallest bubbles appear as perfect spheres; for them, surface tension is strong enough to maintain that spherical shape even against the…
Tapping a Can Won’t Save Your Beer
It happens to the best of us: sometimes our beer gets shaken up during transit. One common reaction to this is to tap the side of the can repeatedly before opening, but a new scientific study shows that tapping doesn’t affect the volume of beer lost. Danish scientists tested over 1,000 cans of beer in…
The Physics of Al Dente
It’s a simple weeknight routine: toss a handful of spaghetti noodles in boiling water, wait a few minutes, and enjoy with the sauce of your choice. But there’s a surprising amount of physics in the humble strand of spaghetti, and a new model focuses on the way spaghetti sags and curls as it cooks. Spaghetti,…
Swinging Jets
In the tiny realm of microfluidics, flows are, in general, completely laminar. That makes mixing a challenge. But it turns out that pumping water steadily into multiple inlets can spontaneously generate oscillations between the jets, allowing dramatic mixing even at low Reynolds numbers. Two inlets in a parallel channel (first image) oscillate steadily over a…
River Avon
One of the challenges in fluid dynamics is considering the instantaneous versus the average. Many flows — especially turbulent ones — are different at every point in space and in time. That’s a lot of data to collect and to wrap one’s head around. So often researchers will average turbulent measurements over a period of…
Flowery Splashes
Plunge a disk into water and you’ll get a dome-like splash that closes back on itself. But what happens when that disk has a patterned surface? In this video, researchers added a wedge-like surface pattern to the disk, creating a splash with petals like a flower. Just as the surface of disk is about to…
Testing Waves in High Gravity
Where waves crash and meet, turbulence is inevitable. But exactly how large waves interact — whether in the ocean, in plasma, or the atmosphere — is far from understood. A new experiment is teasing out a better physical understanding by tweaking a variable that’s been hard to change: gravity. To do so, the researchers conduct…
Spinning Ink Out of Markers
I have to say I’m grateful that my classmates in school never discovered the mess-generating superpower of felt-tipped markers. As the Slow Mo Guys demonstrate here, when you spin or fling these markers, ink will stream out of them. That’s due, in part, to the air vents present near the tips. Markers (and other pens)…
“Viscoelasticity Gives You Wings!”
What happens when you drop a hydrogel bead on a water droplet? Because of the hydrogel’s viscoelasticity and its hydrophilic nature, the rebounding bead carries the droplet with it. As seen in the video above, when the impact energy is small enough, the droplet forms a reverse crown during lift-off, kind of like giving the…