Tag: Helen Czerski

Swans: How do they stay so white? Spit & Sparkle…

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Swans are the gentle giants of my local waterways: floating paragons of snowy serenity that cruise peacefully through muddy brown water amid the rowdy confusion of their smaller brethren.

And they present a puzzle. Around them, mallards, Egyptian geese and Mandarin ducks have plumage so varied that it seems like any little speck of dirt or grime would disappear into the design. But the swans, paddling around in water so opaque that their feet can’t be seen, tip their tail feathers high in the air to forage underwater for the deepest plants—yet they re-emerge an unreasonably pure white. How do they stay so clean?

[…]

Just as a swan uses an oily coating to repel water, to get rid of oil it needs a watery coating. And the answer—discovered only three years ago in a paper published in the journal Advanced Functional Materials—is saliva. A swan’s spit is full of proteins that have a water-loving end and an oil-loving end. Once in a while, the bird distributes saliva on its feathers instead of preen oil, and the oil-loving ends stick to the feathers, leaving the water-loving ends exposed.

This makes the feathers attractive to water, and so allows the watery saliva to penetrate deep into the feathers. Once it’s there, it finds channels lined with tiny wedges. The wedge shapes help surface tension push the water from the center of the feather to the edges, sweeping along and clearing out any tiny droplets of oil or fat on the way.

The feathers get a watery deep cleaning as the tiniest oily contaminants are carried away. After a while, air dries the saliva out, and the surface returns to its normal water-hating state while the swan is restored to its pristine purity.

It’s a fascinating system, and scientists and engineers are now trying to replicate it to make self-cleaning fabrics that we could use. But kudos to the swan, for having evolved the perfect spit-and-sparkle system for keeping itself clean.

Read full article here.

— Helen Czerski, from “How Swans Stay White in Muddy Waters” (Wall Street Journal, June 6, 2024)

DK Photo: May 31, 2023. 4:30 am. Cove Island Park, Stamford, CT. More photos of the swans from that morning here.

Monday Morning Wake-Up Call

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Helen Czerski, “Inside the Dramatic Dance of Raindrops. From drizzles to deluges, a chaotic atmospheric choreography determines the size and shape of precipitation.” (Wall Street Journal, May 2, 2024)

Spring showers can arrive with a vengeance. I was sitting in a parked car a few days ago when a light pitter-patter began on the windshield, and less than a minute later huge raindrops were smacking into the glass, creating a deafening noise and making me extremely grateful I wasn’t outside. But the droplets were falling too fast for me to really see what they were up to before they hit. That seemed like a huge shame because a rainstorm is its own kind of dance party, one with dramatic but chaotic choreography.

Rain starts as water vapor high in the sky; the individual water molecules float free of one another, mixed in with the other gases that make up the atmosphere. When the conditions are right, they condense to join a liquid water droplet or freeze solid onto an ice crystal. At the start, these solid or liquid particles are very small and just drift along with the air currents. But as they grow in mass, they start to fall. Lots of raindrops start off as ice crystals and melt as they fall into warmer air. Once all the droplets are liquid and falling, the dance really gets going.
Continue reading “Monday Morning Wake-Up Call” →

Why Do Ducks Get in a Row?

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The River Thames is beautiful in early summer, and the stretch just upstream of central London is full of birds: motionless herons watching for fish, bustling moorhens poking around the submerged plants, and watchful flocks of preening swans. But as my canoe club paddles along the river, we’re always looking out for our clear favorites: the mother ducks with a fluffy cluster of ducklings tagging along behind.

When they’re lingering at the shore, it all looks slightly chaotic, with baby birds dawdling and exploring as the mother duck keeps an eye on them. But when it’s time to move on, chaos shifts into order as the ducklings line up behind the adult and the convoy moves off together quickly and in perfect formation. It’s mesmerizing to watch, and it’s not accidental. This is all about saving energy.

Swimming is hard work, because water is dense and slightly viscous. At the surface, a large part of the resistance to movement comes from the waves that are produced behind whatever is moving: its wake. This is the familiar wedge-shaped wave pattern that we see behind ships, canoes and ducks alike, and all of those waves carry energy. If you move along the water surface, those waves are always continually generated and so the swimmer needs to put in enough energy to create them. This energy cost is felt as a resistance to movement. There’s also resistance because the water touching the ship or duck is pulled along too, creating additional drag. Continue reading “Why Do Ducks Get in a Row?” →

Miracle. All of it.

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Spring has finally arrived, and it makes me smile every time I step outside. New green leaves are pushing themselves into the sunlight as plants build the solar panels that will fuel them throughout the year. The first spring flowers are already in bloom, and a bright showcase of cheerful rainbow color is rapidly replacing the gray-brown palette of late winter.

I love the constant small surprises as new flowers appear. But each new sighting makes me wish for a superpower: the sort of expanded vision that could show me all the colors these flowers have to offer. Human beings can see some of them, and birds and bees can see a little more. But the potential range of invisible colors is mind-boggling, and science is only just starting to get a grip on it.

Our color vision is neatly summed up in our perception of a rainbow, sweeping from red, the longest wavelength of light that our eyes can detect, to violet, the shortest. But we can’t detect each shade individually; in order to make sense of this continuous spectrum of colors, we use a clever shortcut. Our eyes have three types of cone cell that respond to different colors—red, green and blue. Our brain figures out how much of the light that we see falls into each category, and it recombines that information to construct the myriad colors that we register. It is both beautifully efficient and frustratingly crude…

~Helen Czerski, from Colors That Only Bees and Birds Can See

Notes:

  • Photo: Spring Flowers by Paul.
  • Related Posts: Miracle. All of it.
  • Inspiration: Inspired by Albert Einstein’s quote: “There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.”