FYFD

Tag: biology

  • Morphing Wings Using Real Feathers

    Morphing Wings Using Real Feathers

    Although humanity has long been inspired by bird flight, most of our flying machines are nothing like birds. Engineers have struggled to recreate the ease with which birds are able to morph their wings’ characteristics as they change from one shape to another. Now researchers have built a biohybrid robot, PigeonBot, that uses actual pigeon feathers as part of its morphing design.

    Many species of birds, including pigeons, have Velcro-like hooks in the microstructure of their feathers. These hooks help the flight feathers stick to one another and create a continuous wing surface that air cannot easily slip through, even as the wing drastically changes shape. By using actual feathers, PigeonBot shares this advantage.

    PigeonBot also has a somewhat minimalist design in its articulation, using only a wrist and finger joint in each wing to control shape. The feathers are connected through an elastic ligament, which — along with their microstructure — allows them to smoothly change shape under aerodynamic loads. The end result is a remarkably capable and agile biorobot researchers can use to better understand how birds control their flight. (Image and research credit: L. Matloff et al. and E. Chang et al.; via NPR and Gizmodo)

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    Rattlesnakes Sip Rain From Their Scales

    Getting enough water in arid climates can be tough, but Western diamondback rattlesnakes have a secret weapon: their scales. During rain, sleet, and even snow, these rattlesnakes venture out of their dens to catch precipitation on their flattened backs, which they then sip off their scales.

    Researchers found that impacting water droplets tend to bead up on rattlesnake scales, forming spherical drops that the snake can then drink. Compared to other desert-dwelling snakes, Western diamondbacks have a far more complicated microstructure to their scales, with labyrinthine microchannels that provide a sticky, hydrophobic surface for impacting drops. (Video and image credit: ACS; research credit: A. Phadnis et al.; via The Kid Should See This)

  • The Best of FYFD 2019

    The Best of FYFD 2019

    2019 was an even busier year than last year! I spent nearly two whole months traveling for business, gave 13 invited talks and workshops, and produced three FYFD videos. I also published more than 250 blog posts and migrated all 2400+ of them to a new site. And, according to you, here are the top 10 FYFD posts of the year:

    1. The perfect conditions make birdsong visible
    2. Pigeons are impressive fliers
    3. The water anole’s clever method of breathing underwater
    4. 100 years ago, Boston was flooded with molasses
    5. The BZ reaction is some of nature’s most beautiful chemistry
    6. The labyrinthine dance of ferrofluid
    7. 360-degree splashes
    8. The extraordinary flight of dandelion seeds
    9. Dye shows what happens beneath a wave
    10. Bees do the wave to frighten off predators

    Nature makes a strong showing in this year’s top posts with five biophysics topics. FYFD videos also had a good year: both my Boston Molasses Flood video and dandelion flight video made the top 10!

    If you’d like to see more great posts like these, please remember that FYFD is primarily supported by readers like you. You can help support the site by becoming a patron, making a one-time donation, or buying some merch. Happy New Year!

    (Image credits: birdsong – K. Swoboda; pigeon take-off – BBC Earth; water anole – L. Swierk; Boston molasses flood – Boston Public Library; BZ reaction – Beauty of Science; ferrofluid – M. Zahn and C. Lorenz; splashes – Macro Room; dandelion – N. Sharp; dyed wave – S. Morris; bees – Beekeeping International)

  • Surfing Honeybees

    Surfing Honeybees

    Honeybees have superpowers when it comes to their aerodynamics and impressive pollen-carrying, but their talents don’t end in the air. A new study confirms that honeybees can surf. Wet bees cannot fly–their wings are too heavy for them to get aloft when wet–but falling into a pond isn’t the end for a foraging honeybee.

    Instead, the bee flaps its wings, using them like hydrofoils to lift and push the water. This action generates enough thrust to propel the bee three body lengths per second. It’s a workout the bee can only maintain for a few minutes at a time, but researchers estimate honeybees could cover 5-10 meters in that time. Once ashore, the bee spends a few minutes drying itself, and then flies away no worse for the wear. (Image and research credit: C. Roh and M. Gharib; via NYTimes; submitted by Kam-Yung Soh)

  • Seeing Past the Surface

    Seeing Past the Surface

    Satellite imagery has revolutionized remote sensing and our ability to observe the world around us. But peering past the surface of water has always been next to impossible. We might be able to see the extent of a coral reef from a photo, but thanks to the interplay of light and water, the details are too blurry to identify what species we’re looking at.

    To solve this issue, researchers decided to work backwards, taking everything we understand about the physics of light – refraction, reflections, and so on – and using it to remove the distortions. The result is NASA’s FluidCam, an instrument capable of of taking a video of shallow waters less than 10 m deep, processing it, and producing images with sub-centimeter accuracy showing what lies beneath. Tests in American Samoa revealed details fine enough that scientists were able to identify multiple coral species as well as many of the species of fish inhabiting the reef. 

    With coral reefs changing quickly, this technology may be invaluable for monitoring coral health without actively disrupting these delicate systems. (Image credit: N. Usry; research credit: V. Chirayath and A. Li; via OceanBites; submitted by Kam-Yung Soh) 

  • Whale Feeding

    Whale Feeding

    Whether in groups or as individuals, humpback whales are canny hunters. They herd prey together by encircling them and releasing bubbles that form a “net” that bars escape. Then, the whales lunge through the center with open mouths, gathering prey. Scientists have long wondered whether humpbacks’ unusually long pectoral fins played any role in their hunting. New drone observations of whales feeding (see video below) are beginning to provide some hints.

    The scientific teams observed multiple individual whales feeding under the same circumstances and found that the whales used their fins quite differently. Both used them as additional barriers to prevent prey from escaping, but one whale favored a horizontal fin position that created currents that helped sweep prey into its mouth. The other whale used a more vertical fin position that, while hydrodynamically unfavorable, exposed its bright underside, which seemed to startle prey into fleeing into its darker, more inviting mouth. (Image credit: K. Kosma; video credit: M. Kosma; research credit: M. Kosma et al.; via Science)

  • Sliding Down a Pitcher Plant

    Sliding Down a Pitcher Plant

    Carnivorous pitcher plants supplement their nutrient-poor environments by capturing and consuming insects. The viscoelastic fluid inside them helps trap prey, but fluid dynamics plays a role elsewhere on the plant as well. The inner and outer surfaces of the pitcher are covered in macroscopic and microscopic grooves, seen above, oriented toward the interior of the plant. 

    Researchers found that these grooves trap droplets on the slippery plant through capillary action. Once adhered, the droplet cannot easily move across the grooves, but it can slip along them, carrying the droplet and any insect stuck to it, into the plant. By replicating pitcher-plant-inspired grooves on manmade surfaces, researchers found they were able to better control droplet motion on slippery, lubricant-infused surfaces than in previous work. (Image and research credit: F. Box et al.; via Royal Society; submitted by Kam-Yung Soh)

  • Escaping the Limits of Viscosity

    Escaping the Limits of Viscosity

    For large creatures, it’s not hard to feel the evidence of someone else swimming nearby. But to tiny swimmers water is incredibly viscous and hard to move. These creatures have to swim very differently than their larger cousins, and evidence of their motion dies out quickly. But at least one microorganism,  Spirostomum ambiguum, has discovered a method for overcoming the limits of size and viscosity.

    The single-celled swimmer, when threatened, contracts its body in milliseconds, generating accelerations greater than those seen by fighter pilots. That acceleration is strong enough that it generates a burst of turbulence powerful enough to overcome the natural damping of its viscous surroundings. Within their colonies, S. ambiguum seem to use contraction to send out hydrodynamic signals to neighbors, who pass on the call to arms. To see the colonies in action, check out this previous article. (Image and research credit: A. Mathijssen et al.; via Physics Today; submitted by Kam-Yung Soh)

  • If You Teach a Goose to Fly

    If You Teach a Goose to Fly

    Scientists do all manner of odd things in the name of science. To teach bar-headed geese – birds capable of flying at the altitude of Everest – to fly in a wind tunnel, one group of researchers fostered a group of geese from the moment they hatched. They taught them to fly, first by chasing their bicycling parent and then following her on a motor scooter. Only then could they train the geese to fly in a wind tunnel designed to test how these birds manage to keep flying with only 30% of the oxygen found at sea level*.

    The birds’ secret, it turns out, is metabolic. As the oxygen dropped, so did the temperature of the geese’s blood. Hemoglobin, which binds oxygen in blood cells, is more efficient at lower temperatures, allowing the birds to get more oxygen. At the same time, though, their overall metabolism slowed down, meaning that they required less oxygen overall to function. Taken together, these adaptations make the geese excellent fliers in conditions most animals cannot tolerate. (Image and research credit: J. Meir et al.; via WashPo; submitted by Marc A.)

    * Occasionally I get comments pointing out that drag decreases with altitude, thereby making it easier to cut through the air. While this is true, I can say from my own experience of living and exercising at altitude that, for most of us, the effects of low oxygen levels far outweigh the savings in drag. It’s hard to appreciate a tiny drop in drag when your heart rate is sky high!

  • The Impressive Take-Off of Pigeons

    The Impressive Take-Off of Pigeons

    One reason that peregrine falcons are such amazing fliers is that their prey, pigeons, are no slouches in flight, either. Able to take off vertically and accelerate to 100 kph in two seconds, pigeons are pint-sized powerhouses. With this high-speed video, BBC Earth highlights the mechanics of this vertical take-off. Pigeons begin by bending their legs and jumping high enough that their first downstroke can extend fully and still clear the ground. That gives them a headstart on generating the force they need to propel themselves upward. 

    Note the way the pigeon’s wings move, sweeping from directly behind the bird’s back to a full extension in front of it. With the bird moving vertically, this motion tells us that it’s thrust – not aerodynamic lift – from the wingstroke that’s powering this take-off. In that sense, the pigeon is something like a Harrier jet, using the thrust of air downward to take off vertically. (Image and video credit: BBC Earth)