Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Bouncing Bullets Off Water
With the right shot, it’s possible to skip a bullet off water, as shown in this video from the Slow Mo Guys. The angle of the bullet relative to the water needs to be quite shallow, as this sets the bullet up for the hydrodynamic lift needed to skip. Physically, the mechanism for skipping a…
Soap Film Ruptures
Soap film ruptures are well understood for your typical bubble solution, but what happens when tiny particles get added to the soap film? That’s the question in this recent study. Researchers added 660-nanometer particles, in varying amounts, to their soap films to see how it affected rupture. When they broke the films just after formation…
Spiral Ice Cracks
This odd puddle was found in Arizona after a night with low temperatures around -8 degrees Celsius (18 degrees Fahrenheit). Unlike the concentric rings sometimes seen on ice, this puddle formed one spiraling crack. It’s hard to know exactly what factors played into this formation since it was only found after the fact, but one…
A Glimpse of Earth’s Interior
Lava spurts from the Fagradalsfjall volcano in Iceland in this award-winning photo by Riten Dharia. It’s always bizarre to see molten rock flowing in fountains and rivers because it’s so unlike our daily experiences. Some deeply buried areas of the Earth, including the outer part of the core, are often described as liquid rock, which…
Curved Cracks
When mixtures of particles and fluids dry, they typically leave a pattern of straight cracks. Here researchers explore what happens when the drying film contains bacteria from the family E. coli. Instead of straight cracks, the films form curved ones. With bacteria that rotate or tumble, the crack pattern is spiral-like. With bacteria that swim,…
Nacreous Clouds
Iridescent clouds shine bright over this Finnish sunset. These colorful clouds are nacreous clouds, also known as mother-of-pearl clouds. Formed from ice crystals during frigid conditions in the lower stratosphere, these clouds are most visible before dawn and after sunset, when their high altitude catches sunlight while the lower atmosphere doesn’t. These rare clouds form…
Superradiance in Fluids
A group of excited atoms can collectively emit more photons than they could individually in a phenomenon known as superradiance. Now researchers have shown that vibrating fluids can produce superradiance as well. Similar to other hydrodynamic quantum analogs, the researchers vertically vibrated a pool of liquid at a frequency that produced Faraday waves. Beneath the…
Placental Fluid Dynamics
The placenta, critical as it is to human life and development, is likely the least-studied organ in the body. Reasons for that abound, from the ethics of studying pregnant people to the historical marginalization of female bodies in medical studies. But what little we do know shows that the placenta is quite incredible. Shaped somewhat…
Exploding a Bubble
In this high-speed video, artist Linden Gledhill ignites a mixture of oxygen and hydrogen contained within a soap bubble. As neat as the video is, I decided to take a closer look at the initial detonation with this animation: Even here, it’s hard to appreciate just how fast ignition is; it lasts only a handful…
A Game of Toss
Over the past few years, we’ve seen lots of droplets bouncing and walking on waves. But today’s example is a little different. In this set-up, the wave is a large standing wave that sloshes from side-to-side in a narrow container. As it does, the wave catches and tosses a large ~3mm water droplet. The system…