Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Cracks in Sea Ice
Arctic sea ice often appears as a single extensive sheet when, in reality, it is made up of many smaller sections of ice shifting and grinding against one another under the influence of winds and ocean currents. This can cause cracks–known as leads–to open up between sections of the ice. This animation, constructed from infrared…
Penguins Can Be Colder Than Their Surroundings
Thermal imaging of emperor penguins in Antarctica shows that, in still conditions, large portions of their bodies remain colder than ambient temperatures. In the image above, the heads, beaks, eyes, and flippers of this pair of penguin are the warmest while much of their feathered surface remains several degrees colder than the temperature around them.…
Stopping Jet Break-Up
When a stream of liquid falls, a surface tension effect called the Plateau-Rayleigh instability causes small variations in the jet’s radius to grow until the liquid breaks into droplets. For a kitchen faucet, this instability acts quickly, breaking the stream into drops within a few centimeters. But for more viscous fluids, like honey, jets can…
Skittering Droplets
Water splattered onto a a hot skillet will skitter and skip across the surface on a thin layer of vapor due to the Leidenfrost effect. The partial vaporization of the droplet provides a low-friction cushion for the droplet to glide on and acts as an insulating layer that delays the vaporization of the rest of…
Reader Question: More Standing Waves
corroding-touch asks: So, further to the wave question, how about pressure? How does the pressure in a fixed spot beneath a wave vary, and how does this change with depth? The primary factor for pressure at any point in the water is depth. Deeper water means a higher pressure. So if you imagine your fixed point…
Reader Question: Standing Waves
captainandry asks: What would happen to a fish or swimmer in a standing wave? First of all, check out the video that inspired this question, which shows a standing water wave created in a wave tank. Before we tackle the standing wave, it’s helpful to know what motion exists in a typical water wave. For…
Egg-Spinning Fun
If you have any leftover hard-boiled eggs, you can recreate this bit of fluid dynamical fun. Spin the egg through a puddle of milk, and you’ll find that the egg draws liquid up from the puddle and flights it out in a series of jets. As the egg spins, it drags the milk it touches…
Gravity’s Effect on Bursting Bubbles
In a gravitational field, the pressure in a fluid increases with depth. You can consider it due to the weight of the fluid above. Outside of scuba diving or hiking at altitude, this effect is not one typically given much thought. But what effect can it have at a smaller scale? This video shows the…
Saturn’s Great White Spot
We’ve touched a couple times on Saturnian storms, but this NASA video gives a great overview of the Great White Spot, a storm that appeared in late 2010. Gauging the fluid dynamics of gas giants like Saturn and Jupiter is difficult, in large part because we can see only the outermost portion of the atmosphere.…
Lava in Action
We’ve touched on volcanoes and the fluid dynamics of lava a couple of times here at FYFD, but over at Wired volcanologist Erik Klemetti has some wonderful photos and videos he took while visiting an active lava flow in Hawaii along with great explanations of the flow shapes and processes. Above we see him using a rock…