Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
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An Introduction to Turbulence
With some help from Physics Girl and her friends, Grant Sanderson at 3Blue1Brown has a nice video introduction to turbulence, complete with neat homemade laser-sheet illuminations of turbulent flows. Grant explains some of the basics of what turbulence is (and isn’t) and gives viewers a look at the equations that govern flow – as befits…
Making a Square Vortex
As someone who has played with her share of vortex cannons, I can assure you that messing around with smoke generators and vortex rings is a lot of fun. And in this video, Dianna gives things a little twist: she makes the vortex cannon’s mouth a square instead of a circle. Now, that doesn’t create a…
Carbonation in Microgravity
Bubbly beverages are popular among humans, but there’s surprising complexity underlying their seemingly simply carbonation, as explored in a new Physics Today article. Most drinks get their bubbles from carbon dioxide, which at higher than atmospheric pressures, can stay dissolved inside water and other liquids. When that pressure gets released, any carbon-dioxide-filled gas cavity in the…
The Tacoma Narrows Bridge
One of the most dramatic and famous engineering failures of the twentieth century is also one of the most complicated: the collapse of the Tacoma Narrows Bridge. This early suspension bridge earned the name “Galloping Gurtie” from construction workers while it was still being built because its flexibility made it prone to moving up and down…
Nacreous Clouds
During winter, the polar skies can ignite with mother-of-pearl-like iridescence. Polar stratospheric clouds – also known as nacreous clouds – are a rare, beautiful, and destructive type of cloud found only in high latitudes at altitudes of 15 – 25 km. They are formed from tiny crystals of ice and nitric acid, and they shine…
“Float”
In “Float” artist Susi Sie uses water and oil to create a whimsical landscape of bubbles and droplets. Coalescence is a major player in the action, though Sie uses some clever time manipulations to make her bubbles and droplets multiply as well. Watching coalescence in reverse feels like seeing mitosis happen before your eyes. (Video and…
What Makes Turbulence So Hard
Turbulence – that pestersome, unpredictable, and chaotic state of flow – has been a thorn in the sides of mathematicians, physicists, and engineers for centuries. It is certainly one of – if not the – oldest unsolved problem in physics. Over at Ars Technica, Lee Phillips has a nice overview of the situation, including what…
Inside Hurricane Maria
In addition to looking outward, NASA constantly monitors our own planet using a suite of satellites. In this video, they visualize data taken by the Global Precipitation Measurement Core Observatory of Hurricane Maria two days before it hit Puerto Rico. Instruments on board the satellite measure both liquid and frozen precipitation, giving scientists – and…
Hydraulics Make Spiders So Creepy
There’s something about the way spiders move that many of us find inherently creepy. And that something, it turns out, is fluid dynamical. Unlike humans and other vertebrates, spiders don’t move using two sets of opposing muscles. The natural state of their multi-jointed legs causes them to flex inward. This is why dead spiders have…
Boiling with Sound
Ultrasonic vibrations can boil nanoscale liquid layers, according to a new simulation-based study. Above you see a layer of water initially about 2 nm thick. When the surface it’s on vibrates at frequencies in the 100 GHz range – about a billion times faster than a hummingbird flaps – it superheats the thin layer of…