Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
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…
Driving Instabilities with a Twist
Imagine that you want to study how two fluids mix when a lighter fluid is pushed into a denser one. Conceptually, it’s a straightforward situation. It would be like having a layer of oil under a layer of water and watching what happens. But how do you do that experimentally? Oil won’t naturally stay under water.…
Modeling Oobleck
Oobleck – that peculiarly behaved mixture of cornstarch and water – continues to be a favorite of children and researchers both. Oobleck flows like a liquid when deformed slowly, but try to move it quickly and it will seize up like a solid. This sudden change depends on the tiny particles of cornstarch suspended in the…
Drops That Dig
On extremely hot surfaces, droplets will skitter on a layer of their own vapor, thanks to the Leidenfrost effect. This keeps the liquid insulated from contact with the hot surface. But what if the surface isn’t solid? That situation is what we see above. Instead of soaking into a granular material like a room temperature droplet (left), a…
Pollock Avoided Coiling
Artists are often empirical masters of fluid dynamics, as they must be to achieve the effects they want. Jackson Pollock was particularly known for his so-called dripping technique, in which he dropped filaments of paint from brushes, cans, and even syringes as he moved around a horizontal canvas. (Scientifically speaking, this wasn’t really dripping since the paint…
Streaming Fire
I’m just going to start this one with a blanket statement: DO NOT TRY THIS. Instead, enjoy the fact that the Internet enables us to enjoy the sight of burning gasoline in slow mo without any danger to ourselves. In this video, Gav and Dan capture a burning bucket of gasoline as it’s thrown against glass. One…