Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Dripping, Frozen
The simple drip of a faucet is more complicated when frozen in time. Any elongated strand of water tends to break up into droplets due to surface tension and the Plateau-Rayleigh instability. Whenever the radius of the water column shrinks, surface tension tends to drive water away from the narrow region and toward a wider…
Clogging, In Hourglasses and Crowds
Hourglasses are pretty common, but you’ve probably never given much thought to the way they flow. An hourglass designer has to carefully select the sizing of the neck and the grains. Choosing a neck that’s too small relative to the grain size will result in frequent clogs but choosing too large a neck will make…
Frost Spreading
Frost typically forms when supercooled droplets of water scattered across a surface freeze together. The freezing spreads via tiny ice bridges that link droplets together into a frozen network. The animation above shows this process in action. Freezing starts in a droplet off-screen on the right and quickly spreads. Watch carefully, and you can see…
Researching Wind Turbines
Two of the most awesome things (in my admittedly biased opinion) about fluid dynamics are the amazing facilities we build for experiments and the tests they allow us to do. In this video, you get a behind-the-scenes look at one such facility, used for wind turbine research at Princeton. One challenge of wind turbine research…
Spore Squirting
The fungus Pilobolus spreads its spores with a squirt cannon. Each spore sits on the end of a round fluid-filled pod. Like many plants, the fungus uses a process called osmosis to pump water into the pod. Through osmosis, the fungus increases the concentration of certain molecules inside the pod, which draws water into the pod…
Off on a vacation
Hey guys, Tomorrow (October 14), I’m heading off on vacation for a couple weeks out of range of the Internet. I’ve queued up entries for while I’m gone and my friend Claire from Brilliant Botany (check it out!) has kindly agreed to watch over the Tumblr queue and make sure it posts like it’s supposed to.…
Underwater Explosions in Slow Mo
The Slow Mo Guys bring their high-speed skills to underwater explosions in this new video. The physics of such explosions is very neat (but also incredibly destructive). When the fuse ignites, a blast wave travels outward in a sphere, creating a bubble filled with gas. Eventually, the pressure of the surrounding water is too great…
Hummingbird Drinking
Hummingbirds are master acrobats, able to hover and drink simultaneously before flitting off to the next flower. At first glance, you might expect that their tongues are simply tiny straws that use surface tension and capillary action to draw up nectar. But it turns out that process is just too slow for the fast-paced birds.…
Floating on a Granular Raft
A thin layer of hydrophobic particles dispersed at an oil-water interface is strong enough to prevent a water droplet from coalescing. The researchers refer to this set-up as their granular raft. As the red-dyed water droplet gets larger (top row), it deforms the raft more and more, but the grains continue to keep the drop…
“Gargantua”
Peering into a vortex feels like staring into an abyss in the Julia Set Collective’s “Gargantua”. Like their previously featured works, this video uses a macro perspective on fluid phenomenon to create an alternate sense of scale. Instead of a whirlpool, we could be observing a wormhole. Part of this is a matter of fooling…