FYFD

Tag: physics

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    Ripple Bugs

    Ripple bugs are a type of water strider capable of moving at a blazing fast 120 body lengths per second across the water surface. In addition to their speed, ripple bugs are incredibly agile and are active almost constantly. Researchers believe they’ve found the insect’s secret: feather-like hydrophilic fans that spread on contact with the water. These fans help the insects push off the water and steer, but they require no effort to open and close. They’ve even adapted the technique to bio-inspired robots and seen improvements in speed, agility, and efficiency. (Video credit: Science; research credit: V. Ortega-Jimenez et al.)

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    Leaves Dance in the Wind

    Once a breeze kicks up, leaves on a tree start dancing. Every tree’s leaves have their own shapes, some of which appear very different from other trees. But their dances have patterns, as this video shows. In it, researchers explore how leaves of different shapes deform in the wind and how they can decompose that motion to compare across leaves. (Video and image credit: K. Mulleners et al.; via GFM)

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  • Panama’s Missing Pacific Upwelling

    Panama’s Missing Pacific Upwelling

    Strong seasonal winds blowing from the Atlantic typically push water away from Panama’s Pacific coast, allowing deeper, colder waters to rise up. This upwelling cools reefs and feeds phytoplankton blooms, both of which support the rich marine life found there. But in early 2025, the upwelling didn’t occur.

    Normally, coastal ocean temperatures drop to about 19 degrees Celsius during upwelling. Instead, temperatures only reached 23.3 degrees at their coolest. Wind seems to be the missing ingredient: winds from the Atlantic side were short-lived and 74% less frequent than in typical years.

    That lack of upwelling is expected to carry consequences to Panama’s economy. About 95% of the country’s fishing catch comes from the Pacific side, so any drop in fish populations will be felt. The open question remains: was the missing upwelling a singular extreme event or a harbinger of a new normal? (Image credit: R. Heuvel; research credit: A. O’Dea et al.; via Eos)

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  • A Soft Cell in Microgravity

    A Soft Cell in Microgravity

    There are many shapes that can be tiled to fill space, but nearly all of them have sharp corners. Last year, mathematicians identified a new class of shapes, known as “soft cells,” that feature curved edges and faces but very few sharp corners. Like traditional polyhedrals, soft cells can tile to fill a space completely without overlapping or gapping.

    Now the researchers, with some help from astronauts aboard the ISS, have brought one of their soft cells to life. Using an edge skeleton to guide the shape, astronaut Tibor Kapu filled the skeleton with water, which, in microgravity, formed a perfect soft cell, complete with faces curved by surface tension to their minimal area. See it in action below. (Image and video credit: HUNOR/NASA; research credit: G. Domokos et al.; via Oxford Mathematics)

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  • “Legends of the Falls”

    “Legends of the Falls”

    Strong winds blew curtains of mist across Skรณgafoss in this image of nesting northern fulmars by photographer Stefan Gerrits. Despite water’s high density compared to air, fine droplets are able to stay aloft for long periods, given the right breeze. Mists, fogs, and sea spray can float surprising distances; droplets exhaled from our lungs can persist even farther. (Image credit: S. Gerrits; via Colossal)

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  • Controlling Hovering

    Controlling Hovering

    Hummingbirds and many insects hover when feeding, escaping predators, and mating. While scientists have decoded the mechanics of a hummingbird’s figure-8-like hovering wingstroke, it’s been harder to understand how the creatures control their hovering. Most of our attempts to control hovering require more computational power than hummingbirds and insects are thought to have. But this study describes a new control scheme: one that allows stable, real-time hovering with little computational cost. (Image credit: J. Wainscoat; research credit: A. Elgohary and S. Eisa; via APS)

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    Marangoni Bursting With Surfactants

    A few years ago, researchers described how an alcohol-water droplet atop an oil bath could pull itself apart through surface tension forces. Dubbed Marangoni bursting, this phenomena has shown up several times since. Here, researchers explore a twist on the behavior by adding surfactants to see how they affect the bursting phenomenon. (Video and image credit: K. Wu and H. Stone; via GFM)

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  • Acoustically Trapping Nanoparticles

    Acoustically Trapping Nanoparticles

    Micrometer-sized particles can be trapped in place against a flow using acoustic waves. But smaller nano-sized particles feel less radiation pressure from acoustic waves, and so keep moving in the flow. But new work shows that it is possible to trap those nanoparticles with some additional help.

    In this case, researchers seeded their flow with microparticles that were held in place by acoustic waves against the background flow. When nanoparticles were added to the mix, they remained trapped in the wells between microparticles due to a combination of acoustic forcing and the hydrodynamic shielding of the nearby large particles. (Image credit: P. Czerwinski; research credit: A. Pavliฤย andย T. Baasch; via APS)

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  • In Deep Lakes, Mixing is Disappearing

    In Deep Lakes, Mixing is Disappearing

    With a depth of nearly 600 meters, Crater Lake in Oregon is the deepest lake in the United States. It’s known for its brilliant blue hue and startling clarity. But, like other deep lakes, Crater Lake is changing as temperatures warm. It’s edging ever closer to a day where its deep, cold waters no longer mix.

    Although the details of mixing vary from lake to lake, older records show that most deep lakes would overturn and fully mix on a frequency that ranged from twice a year to every seven years. This overturning happens when winds push frigid, near-frozen water. As that water approaches the shoreline, it gets forced downward, where the pressure at depth makes the cold water denser still, causing it to sink beneath the warmer water layer near the lake bottom. That kicks off larger-scale mixing that redistributes oxygen, nutrients, and toxins in the lake.

    When this regular mixing stops, the entire ecosystem gets affected. Over time, oxygen gets depleted in deeper in the lake, leaving a dead zone unable to support fish and other aquatic life. Meanwhile, longer and warmer growing seasons favor phytoplankton and algae that cloud the waters and disrupt a lake’s unique ecology.

    For a much more detailed look at deep lake mixing and the changes we’re seeing, check out this article over at Quanta Magazine. It’s a longer read but well worth your time. (Image credit: N. Perez Aguilar; see also: Quanta Magazine)

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  • “Melting Snowflake”

    “Melting Snowflake”

    It’s hard to preserve something as ephemeral as a snowflake, as seen in this microphotograph by Michael Robert Peres. Despite the old adage, it is possible to make identical snowflakes, but it requires mirroring the freezing conditions exactly, including both temperature and humidity. Here, the snowflake’s crystalline structure survives as a ghost in a melting droplet. (Image credit: M. Peres; via Ars Technica)

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