Search results for: “art”

Gravity Waves on Mars
It may look like grainy, black and white static from a 20th-century television, but this animation shows what may be the first view of gravity waves seen from the ground on another planet. The animation was stitched together from photos taken by the Mars Curiosity rover’s navigation camera, and it shows a line of clouds approaching the rover’s position.
Gravity waves are common on Earth, appearing where disturbances in a fluid propagate like ripples on a pond. In the atmosphere, this can take the form of stripe-like wave clouds downstream of mountains; internal waves under the ocean are another variety of gravity wave. If these are, in fact, Martian gravity waves, they are likely the result of wind moving up and over topography, much like their Terran counterparts. (Image credit: NASA/JPL-Caltech/York University; research credit: J. Kloos and J. Moores, pdf; via Science; h/t Cocktail Party Physics)
April 24, 2017
The Flying Draco
Nature includes many animals that are so-called fliers: flying squirrels, flying snakes, and draco lizards, to name a few. These animals aren’t true fliers like birds, bats, or insects, though. Instead, they are expert gliders, able to produce enough lift to control their descent and land safely at a distance far greater than a normal leap could carry them. Like the flying squirrel, the draco lizard extends a thin membrane that acts as its wings. The additional area provides enough lift that the lizards can glide as far as 60 m (200 ft) while only losing 10 m (33 ft) in altitude. That’s an impressive glide ratio – about 3 times better than the Northern flying squirrel and twice as good as a wingsuit. (Video credit: BBC/Planet Earth II)
April 21, 2017
Reducing Drag with Bubbles
Large ships experience a great deal of drag due to friction between their hull and the water. One method shipbuilders are considering to combat this drag is the use of bubbles, which have been found to reduce drag by up to 40%. The physical mechanism behind this drag reduction is not yet understood, but a recent study suggests that bubble size and bubble coalescence play an important role.
Researchers introduced surfactants into bubbly boundary layers and found that the reductions in drag evaporated as soon as the surfactants spread. Adding only 6 parts per million of the surfactant decreased average bubble size from 1 mm to 0.1 mm and helped prevent the bubbles from growing via coalescence. The implications are that bubble-induced drag reduction could be extremely sensitive to water conditions. (Image credit: G. Kiss; research credit: R. Verschoof et al.)
April 18, 2017
Hawaii’s Lava
Sometimes the best way to appreciate a flow is standing still. In “Hawaii – The Pace of Formation” filmmakers explore how the Big Island is constantly changing, from fresh lava flows to towering waterfalls. Much of the footage presented is timelapse, which gives viewers a different perspective on familiar subjects; it highlights the similarities between clouds and the ocean, and it reminds us that a lava flow and the syrup flowing down a stack of pancakes have a lot in common. To me, this is one of the most beautiful parts of fluid dynamics: physics of flows on different length-scales and time-scales – even in different fluids – are still very much the same. (Video credit: A. Mendez et al.)
April 17, 2017
Water Skiing Beetles
Waterlily beetles employ an unusual method of getting around: they skim across the water surface. The beetles are mostly covered in tiny hairs that help make their body hydrophobic (water-repellent) – a common adaptation for insects that spend their time sitting on the water’s surface – but the beetles also have hydrophilic claws on their legs that help anchor them to the water’s surface. When they need to move quickly, the beetles lean upright and start flapping their wings, creating thrust that helps push them along the interface. Between water’s viscosity and drag from the waves the insect generates, it has to expend a lot of energy for this method of travel – more than these insects do flying in air – but researchers suspect that staying at the surface could remain beneficial for the beetles because it’s easier to locate their floating food sources this way. (Image credit: H. Mukundarajan et al., source; via New Scientist)
April 13, 2017
Simulating Thunderstorms
With today’s supercomputing power, it’s possible to simulate entire thunderstorms to study how and why some of them can spawn deadly tornadoes. The animation above comes from a computer simulation of a supercell thunderstorm. The simulation uses initial conditions from a 2011 storm that produced an EF-5 tornado – the highest category of tornado, based on its wind speeds. To see more of the simulation, check out the video below. One thing that might surprise you is just how enormous the towering supercell clouds are compared to the tornado produced in the simulation. Often what we can see of a storm from the ground is only the tiniest part of what goes into producing it. (Image credit: L. Orf et al., source; GIF via @popsci; video credit: UWSSEC)
April 12, 2017
Staying Cool in the Outback
Daytime temperatures in the Australian outback can soar, creating a harsh environment for life. Red kangaroos use several methods to regulate their body temperature during the hottest part of the day. They shelter under trees to escape the sun, they dig away the solar-heated topsoil and flop down in cooler soil, and they lick their forearms. Like our wrists, kangaroo forearms have a network of blood vessels near the surface. As their saliva evaporates, it cools the skin and the blood vessels beneath it. Humans are cooled the same way when our sweat evaporates, but a more kangaroo-like trick for cooling off is running cold water over your wrists. (Video credit: BBC/Planet Earth)
April 7, 2017
Breaking Wave
This animation shows a cinemagraph of a breaking wave photographed by Ray Collins. The motion was inferred and digitally added by a second artist, Jersey Maria. The result is hypnotic, as if we are traveling beside the wave and watching it tear apart ever so slowly. The wave seems to be poised on a tipping point, only breaking up along its back edge, when instinct tells us it will keep steepening and tipping forward until its top curl crashes down in a wave of white foam. Surf photography like Collins’ work shows us an alternative perspective on waves, their power frozen into a single instant. Reanimated, it feels like we’re seeing the wave in hyper-slow-motion, watching every tiny movement of water before everything crashes down. Even if it’s not physically realistic, it is an awesome view. (Image credit: R. Collins / J. Maria, source, original; via Iwan A.)
April 6, 2017
Ice Bridges
During winter, Canada’s Arctic Archipelago, home of the Northwest Passage, generally fills with sea ice. These ice bridges form in the long and narrow straits between islands. A new paper models ice bridge formation and break-up, showing that ice bridges can only form when ice floating in the strait is sufficiently thick and compact. To form a bridge, wind must first push the ice together and then frictional forces between individual pieces of ice must be large enough to resist wind or water driving them apart. As temperatures drop, the individual ice chunks can then freeze together into solid sheets until summer returns.
The existence of a critical thickness and density of the ice field for ice bridge formation has important implications for climate change. As Arctic temperatures warm for longer periods, these waters may no longer generate ice of sufficient thickness and quantity for ice bridges to form. Since ice bridges serve as important oases for marine mammals and sea birds and help isolate Arctic sea ice from warmer waters, their loss will have a profound impact on both Arctic ecology and global climate. (Image credit: NASA Earth Observatory; research credit: B. Rallabandi et al.; via Physics Buzz)
April 4, 2017
Acrylic and Oil
Photographer Alberto Seveso is well-known for ink in water art, some of which FYFD has featured previously (1, 2, 3). More recently, he’s been experimenting with alternative methods, dropping fluids like acrylic paint into sunflower oil. The effect is quite different but no less beautiful. Because the paint and oil are immiscible, the boundaries between the two fluids are much more clearly defined and highlighted in an iridescent sheen. Instead of appearing like billowing waves of silk, the paint forms abstract and alien shapes driven by gravity, inertia, and density differences. For many more great examples, check out Seveso’s website. (Photo credit: A. Seveso)
March 31, 2017

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