Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
The Microscopic Ocean
When you’re the size of plankton, water may as well be molasses. Viscosity rules at these scales, and swimming plankton leave distinctive wakes that are slow to dissipate. Fish that feed on plankton use these trails to find their prey. But this microscopic world is changing as the ocean warms. At higher temperatures, water is less viscous, and plankton…
Fast-Switching Multi-Material 3D Printer
For 3D printers to reach their potential, they need to handle more than one material and be able to swap quickly and seamlessly between them. That’s a tall order given how different materials like silicone and wax are. But a new 3D printer tackles that challenge using microfluidic nozzles designed extrude multiple fluids in quick succession. The nozzle controls which fluid…
2019 APS DFD Schedule
It’s time for the annual American Physical Society Division of Fluid Dynamics meeting, and once again, I’ll be attending. If you’ve been scanning the program wondering where I am, wonder no more! Here’s a run-down of the talks and events I’ll be appearing at: “All the Faces of Fluid Dynamics” Panel – Sunday, Nov 24,…
Wave Clouds in the Front Range
Last Sunday night metro Denver was treated to a rare sight: clouds resembling breaking waves formed near sunset. These are Kelvin-Helmholtz clouds, and the comparison to ocean waves is apt, since the same physics is behind both. Winds were unusually calm near the ground Sunday night, but strong winds blew at the altitude just above…
Finding New States of Matter
As children we’re taught that there are three basic states of matter: solids, liquids, and gases. The latter two are known scientifically as fluids. But the world doesn’t divide quite so simply into those three categories, and scientists have since named several other states of matter, including plasmas, superfluids, and Bose-Einstein condensates. Many of these types of matter…
Coke and Butane Rockets
Rocket science has a reputation for being an incredibly difficult subject. But while there’s complexity in the execution, the concept behind rockets is pretty simple: throw mass out the back really fast and you’ll move forward. Whether you’re talking about a Saturn V or these Coke-and-butane-powered bottles, the basic principle is the same. These rockets get their…
Making Drops Stick
As you may have noticed when washing vegetables, many plants have superhydrophobic leaves. Water just beads up on their surface and slides right off. This is a useful feature for plants that want to direct that water toward their roots, but it’s a frustration in agriculture, where that superhydrophobicity means extra spraying of pesticides in order to…
Whiskey Stains
Complex fluids leave behind fascinating stains after they evaporate. We’ve seen previously how coffee forms rings and whisky forms more complicated stains as surface tension changes during evaporation drive particles throughout the droplet. Now researchers are considering the differences between traditional Scottish whisky, which ages in re-used, uncharred barrels, and American whiskeys like bourbon, which are required to age…
“Mocean”
Ocean waves are endlessly fascinating to watch. In “Mocean,” cinematographer Chris Bryan captures them in ways few ever see, thanks to his high-speed camera. Honestly, this film is so gorgeous that I don’t want to distract you with the science, so just go watch! … All done? Pretty wonderful, right? There’s nothing quite like seeing those holes…
Leidenfrost Stars
Atop a very hot surface, liquids can instantly vaporize, leaving a drop levitating on a layer of its own vapor. These Leidenfrost droplets demonstrate all kinds of interesting behaviors, including self-propulsion, explosion, and star-shaped oscillations, like those above. The oscillation is driven by feedback between the drop and its vapor layer. Interestingly, the drops are capable of sustaining more than…