Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
When Shear Meets Slip
One of the classic concepts students learn early in their fluids education is the no-slip condition. In essence, this idea says that friction between a solid object — say, a wall — and the fluid immediately next to it is such that no movement is possible where they meet. The fluid cannot “slip” along the…
Alien Eggs? A Virus?
Nope, they’re hydrogel beads! The team at Chemical Bouillon seem to have once again coated them in something like paint before placing them in water. As the gel beads absorb water, they expand, tearing through their coating. The result is weirdly mesmerizing and kind of creepy. It’s no wonder that special effects artists have historically…
How Well Do Masks Work?
Many mixed messages have been spread about the efficacy of masks in preventing transmission of COVID-19. Nevertheless, there is good evidence that they help, as discussed in this video from It’s Okay to Be Smart. Much of the video shows schlieren imaging of a (healthy) individual engaging in regular activities – like talking, breathing, and…
Shake It!
Vibrate a pool of water, and you’ll get Faraday waves, ripple-like excitations that form their own distinctive pattern compared to the driving vibration. But you don’t have to vibrate a pure liquid to see Faraday waves. A recent study observed them in vibrated earthworms! Odd as this may sound, the results make sense. When anesthetized…
Leaping Hoops
Some water-walking insects are able to leap off a watery interface. One way to model these creatures is with elastic hoops, which can also propel themselves off the water’s surface. In this video, researchers explore some of the factors that affect the jump, like hoop geometry, material, and hydrophobic coatings. Wider hoops jump better than…
Ejecting Water from a Smartwatch
Making electronics water-resistant can be a challenge, but as this Slow Mo Guys video demonstrates, engineers have some clever ways to deal with unwanted liquids. The Apple Watch, for example, uses its speakers to eject water that gets into the watch during immersion. As seen above, the vibration of the speakers ejects most of the…
Branching Sparks from Senko-hanabi
Senko-hanabi are a Japanese firework, somewhat similar to a sparkler. But instead of being driven by burning powder, the senko-hanabi’s sparks come from bursting liquid droplets undergoing an exothermic reaction with air. Chemistry aside, the effect is similar to what goes on in soda water. As bubbles within the liquid nucleate and move to the…
Internal Waves in the Andaman Sea
Differences in temperature and salinity create distinct layers within the ocean. When combined with flow over submerged topography — underwater canyons, mountains, and reefs — it makes waves. But those waves aren’t always apparent when sitting at the surface. Instead, they travel along those ocean layers as internal waves that can be as tall as…
The Vortex Beneath a Drop
While we’re most used to seeing levitating Leidenfrost droplets on a solid surface, such drops can also form above a liquid bath. In fact, the smoothness of the bath’s surface, combined with mechanisms discussed in a new study, means that drops will levitate at a cooler temperature over a liquid than they will over a…
Making Waves
The Seoul Aquarium is now home to an enormous crashing wave, courtesy of design company d’strict. Check out several different views of the anamorphic illusion in their video above. There’s no word on the techniques used to generate the animation, but it’s certainly a cool visual! (Image and video credit: d’strict; via Colossal)