A typical lawn sprinkler features various nozzles arranged at angles on a rotating wheel; when water is pumped in, they release jets that cause the wheel to rotate. But what would happen if the water were sucked into the sprinkler instead? In which direction would the wheel turn then, or would it even turn at all? That’s the essence of the “reverse sprinkler” problem that physicists like Richard Feynman, among others, have grappled with since the 1940s. Now, applied mathematicians at New York University think they’ve cracked the conundrum. […]

“We found that the reverse sprinkler spins in the ‘reverse’ or opposite direction when taking in water as it does when ejecting it, and the cause is subtle and surprising.” […] found that the reverse sprinkler rotates a good 50 times slower than a regular sprinkler, but it operates along similar mechanisms, which is surprising. […]

The reverse sprinkler problem is associated with Feynman because he popularized the concept, but it actually dates back to a chapter in Ernst Mach’s 1883 textbook The Science of Mechanics (Die Mechanik in Ihrer Entwicklung Historisch-Kritisch Dargerstellt). Mach’s thought experiment languished in relative obscurity until a group of Princeton University physicists began debating the issue in the 1940s.

{ ArsTechnica | Continue reading }

acrylic on canvas { David Hockney, A Lawn Being Sprinkled, 1967 }

California Water Futures Begin Trading Amid Fear of Scarcity

Water is joining gold, oil and other commodities traded on Wall Street […] Farmers, hedge funds and municipalities alike are now able to hedge against — or bet on — future water availability in California, the biggest U.S. agriculture market and world’s fifth-largest economy. […]

The futures are tied to the Nasdaq Veles California Water Index, which was started two years ago and measures the volume-weighted average price of water.

{ Bloomberg | Continue reading }

California is gonna have to ration water. You wanna know why? Because they send millions of gallons of water out to sea, out to the Pacific. Because they want to take care of certain little tiny fish, that aren’t doing very well without water.

{ Donald J. Trump | Continue reading }

When privately owned land vanishes under the water, who does it belong to?

The problem is a result of the state’s rapidly changing landscape. About 80 percent of Louisiana’s coast is privately owned. But, under an old law, as coastal erosion and sea level rise turn the land into open water the area becomes property of the state, including the mineral rights underneath.

Private landowners have become more adamant about restricting access to water on their property in order to assert their claim to the minerals underneath it. But boaters often have difficulty figuring out where private property ends and public waterways begin. Since 2003, Louisiana law does not require landowners to post signs demarcating their property. The resulting confusion led the Bass Anglers Sportsman Society, or BASS, to announce in 2017 that it would no longer host professional fishing tournaments in Louisiana tidal waters, where fishers risk being arrested.

{ NOLA | Continue reading }

{ Scott Kelly and Ben Polkinghorne, Signs of the Times, 2017 }

Whatever goes down the sink, shower, washing machine and toilet is transferred to one of about 14,000 U.S. wastewater treatment plants. While those plants are good at neutralizing sewage microorganisms that can make people sick or pollute waterways, they can miss chemicals that are linked with our changing lifestyles.

The biggest change since most treatment plants were designed? The explosion of pharmaceutical use by Americans. […] About 60% of American adults take at least one prescription pill every day. Residue from those pills travels to treatment plants and waterways.

{ Axios | Continue reading }

cabinet, wood, glass, metal, paint assorted marine debris, plastic, rope { Mark Dion, Cabinet of Marine Debris, 2014 }

How much water goes into a cup of tea? Somewhere around 30 litres of water is required for tea itself, 10 litres for a small dash of milk and a further 6 litres for each teaspoon of sugar. This means that a simple cup of tea with milk and two sugars could actually require 52 litres of water.

{ ResearchGate | Continue reading }

related { A Corpus Study of ‘Cup of [tea]’ and ‘Mug of [tea]’ | PDF }

oil on canvas { Roy Lichtenstein, Bread in Bag, 1961 }

New scientific test finds up to 75 litres of urine in public pools. Hot tubs were found to have far higher urine levels. One hotel Jacuzzi had more than three times the concentration of sweetener than in the worst swimming pool

I’ve studied all the body’s fluids and used each in diagnosing disease, and urine stands out in the wealth of information it grants about a patient’s condition

Distilled urine from female cattle currently fetches at least as much as milk in India

art { Andy Warhol, Oxidation Painting, 1978 | copper metallic pigment and urine on canvas }

Piper Jaffray analyst Stan Meyers said animated films generally cost about $100 million to make, as well as an additional $150 million to promote.

An executive producer who wants to drastically cut costs traditionally has two choices: water and hair. Those are the most expensive things to replicate accurately via animation. It’s no mistake that the characters in Minions, the most profitable movie ever made by Universal, are virtually bald and don’t seem to spend much time in the ocean.

{ Bloomberg | Continue reading }

Redbird Reef is an artificial reef located in the Atlantic Ocean, off the coast of Slaughter Beach, Delaware.

The reef comprises 714 ‘Redbird’ New York City Subway cars, 86 retired tanks and armored personnel carriers, eight tugboats and barges, and 3,000 tons of ballasted truck tires.

{ Wikipedia | Continue reading }

photo { Stephen Mallon }

“Water fountains have been disappearing from public spaces throughout the country over the last few decades,” lamented Nancy Stoner, an administrator in the Environmental Protection Agency’s water office. […]

By 1930, Chapelle says, bottled water had become “low class,” used only in offices and factories that couldn’t afford plumbing.

Attitudes began to shift in the 1970s, when Europe’s Perrier set its sights on the American market. In 1977, the company spent $5 million on an advertising campaign in New York, selling itself as a chic, upscale product. Yuppies lapped it up. “It was a lifestyle-defining product,” Chapelle says. By 1982, U.S. bottled-water consumption had doubled to 3.4 gallons per person per year. […]

U.S. consumption of bottled water quadrupled between 1993 and 2012 (reaching 9.67 billion gallons annually). […]

Today, 77 percent of Americans are concerned about pollution in their drinking water, according to Gallup, even though tap water and bottled water are treated the same way, and studies show that tap is as safe as bottled.

{ Washington Post | Continue reading }

art { Roy Lichtenstein, Girl in Water, 1965 }

The weather impacts not only upon our mood but also our voice. An international research team has analysed the influence of humidity on the evolution of languages.

Their study has revealed that languages with a wide range of tone pitches are more prevalent in regions with high humidity levels. In contrast, languages with simpler tone pitches are mainly found in drier regions. This is explained by the fact that the vocal folds require a humid environment to produce the right tone.

The tone pitch is a key element of communication in all languages, but more so in some than others. German or English, for example, still remain comprehensible even if all words are intonated evenly by a robot. In Mandarin Chinese, however, the pitch tone can completely change the meaning of a word.

{ EurekAlert | Continue reading }

During sexual stimulation, some women report the discharge of a noticeable amount of fluid from the urethra, a phenomenon also called “squirting.” To date, both the nature and the origin of squirting remain controversial. In this investigation, we not only analyzed the biochemical nature of the emitted fluid, but also explored the presence of any pelvic liquid collection that could result from sexual arousal and explain a massive fluid emission. […]

The present data based on ultrasonographic bladder monitoring and biochemical analyses indicate that squirting is essentially the involuntary emission of urine during sexual activity, although a marginal contribution of prostatic secretions to the emitted fluid often exists.

{ The Journal of Sexual Medicine | Continue reading }

photo { Spot }

The process is called reverse osmosis (RO), and it’s the mainstay of large-scale desalination facilities around the world. As water is forced through the membrane, the polymer allows the water molecules to pass while blocking the salts and other inorganic impurities. Global desalination output has tripled since 2000: 16,000 plants are up and running around the world, and the pace of construction is expected to increase while the technology continues to improve. […]

Seawater desalination, in fact, is one of the most expensive sources of fresh water. The water sells—depending on site conditions—for between $1,000 and $2,500 per acre-foot (the amount used by two five-person U.S. households per year). Carlsbad’s product will sell for around $2,000, which is 80 percent more than the county pays for treated water from outside the area. […]

Already, some 700 million people worldwide suffer from water scarcity, but that number is expected to swell to 1.8 billion in just 10 years. Some countries, like Israel, already rely heavily on desalination; more will follow suit. In many places, “we are already at the limit of renewable water resources, and yet we continue to grow,” says John Lienhard, a mechanical engineer and director of the Center for Clean Water and Clean Energy at MIT. “On top of that we have global warming, with hotter and drier conditions in many areas, which will potentially further reduce the amount of renewable water available.”

{ Technology Review | Continue reading }

art { Evander Batson }

Why do fingers get wrinkly in the water? […]

A hypothesis has been proposed which suggests that the wrinkling might be an evolutionary adaptation to make the handling of objects underwater easier. Wrinkling creates a kind of drainage path for water and so enhances the grip on an object (this is called a ‘rain tread’ hypothesis). In order to test if this hypothesis is true Kareklas et al. have recruited volunteers and tested their ability to transfer wet objects when the fingers are wrinkled and not. […]

20 participants had to transfer glass marbles from one container to another in two different conditions (1) take the marble from a container with water pass it through a small hole and put into an empty container and (2) take the marble from a container without water pass it through a small hole and put into an empty container. […]

When the marble ball was dry there was no difference between the transfer time with wrinkly and smooth fingers. However, when the marble was wet then on average it took 12% less time to transfer the object with wrinkly fingers. Therefore, the study concluded that the wrinkling of fingers improves the handling of wet objects (which supports the rain tread hypothesis). Why are our fingers not always wrinkled then? In paper’s discussion Kareklas et al. suggest that there potentially are some fitness trade-offs to the wrinkly fingers. Maybe wrinkled fingers are less sensitive to pain, pressure, heat etc. and are therefore damaged easier, which would explain why it is not good to always have those wrinkles.

{ The Question Gene | Continue reading }

The work done in this room lies at the heart of a department that handles some of the UK’s most cutting-edge research on forensics and anatomy. […]

The hand is Meadows’ area of focus. Variations in scars, skin pigmentation, the smallest nooks and crannies of the fingernail and, most importantly, superficial vein patterns: all of these can build a body of evidence and allow the police to identify an offender in an incriminating photograph. “The back of the hand is part of the anatomy that an offender is quite happy to have in an image, whereas they wouldn’t necessarily want their face captured,” Meadows says. In 2009, Cahid’s work was instrumental in the Neil Strachan case, part of Scotland’s biggest paedophile ring. His unusually distorted lunula (the white half moon at the bottom of a nail) helped identify and convict him.

Meadows and her colleagues have built up the UK’s only database of the hand’s vein patterns, with around 800 samples. Of the 40 or so cases they have worked on, their data have resulted in over 80 per cent of suspects changing their plea.

{ FT | Continue reading }

When a coin falls in water, its trajectory is one of four types determined by its dimensionless moment of inertia I∗ and Reynolds number Re: (A) steady; (B) fluttering; (C) chaotic; or (D) tumbling. The dynamics induced by the interaction of the water with the surface of the coin, however, makes the exact landing site difficult to predict a priori.

Here, we describe a carefully designed experiment in which a coin is dropped repeatedly in water to determine the probability density functions (pdf) associated with the landing positions for each of the four trajectory types, all of which are radially symmetric about the centre drop-line.

{ arXiv | PDF }

There are many theories about why humans cry ranging from the biophysical to the evolutionary. One of the most compelling hypotheses is Jeffrey Kottler’s, discussed at length in his 1996 book The Language of Tears. Kottler believes that humans cry because, unlike every other animal, we take years and years to be able to fend for ourselves. Until that time, we need a behavior that can elicit the sympathetic consideration of our needs from those around us who are more capable (read: adults). We can’t just yell for help though—that would alert predators to helpless prey—so instead, we’ve developed a silent scream: we tear up. […]

In a study published in 2000, Vingerhoets and a team of researchers found that adults, unlike children, rarely cry in public. They wait until they’re in the privacy of their homes—when they are alone or, at most, in the company of one other adult. On the face of it, the “crying-as-communication” hypothesis does not fully hold up, and it certainly doesn’t explain why we cry when we’re alone, or in an airplane surrounded by strangers we have no connection to. […]

In the same 2000 study, Vingerhoet’s team also discovered that, in adults, crying is most likely to follow a few specific antecedents. When asked to choose from a wide range of reasons for recent spells of crying, participants in the study chose “separation” or “rejection” far more often than other options, which included things like “pain and injury” and “criticism.” Also of note is that, of those who answered “rejection,” the most common subcategory selected was “loneliness.”

{ The Atlantic | Continue reading }

photo { Adrienne Grunwald }

First, about how glaciers turn into ocean water.

Consider this experiment. Take a large open-top drum of water and poke a hole near the bottom. Measure the rate at which water comes out of the hole. As the amount of water in the drum goes down, the rate of flow out of the hole will normally decrease because the amount of water pressure behind the hole decreases. Now, have a look at a traditional hourglass, where sand runs from an upper chamber which slowly empties into a lower chamber which slowly fills. If you measure the rate of sand flow through the connecting hole, does it decrease in flow rate because there is, over time, less sand in the upper chamber? I’ll save you the trouble of carrying out the experiment. No, it does not. This is because the movement of sand from the upper to lower parts of an hourglass is an entirely different kind of phenomenon than the flow of water out of the drum. The former is a matter of granular material dynamics, the latter of fluid dynamics.

Jeremy Bassis and Suzanne Jacobs have recently published a study that looks at glacial ice as a granular material, modeling the ice as clumped together ice boulders that interact with each other either by sticking together or, over time, coming apart at fracture lines. This is important because, according to Bassis, about half of the water that continental glaciers provide to the ocean comes in the form of ice melting (with the water running off) but the other half consists of large chunks (icebergs) that come off in a manner that has been very hard to model.

{ Greg Laden/ScienceBlogs | Continue reading }

The unavoidable truth is that sea levels are rising and Miami is on its way to becoming an American Atlantis. It may be another century before the city is completely underwater (though some more-pessimistic­ scientists predict it could be much sooner), but life in the vibrant metropolis of 5.5 million people will begin to dissolve much quicker, most likely within a few decades. […]

South Florida is not the only place that will be devastated by sea-level rise. London, Boston, New York and Shanghai are all vulnerable, as are low-lying underdeveloped nations like Bangladesh. But South Florida is uniquely screwed, in part because about 75 percent of the 5.5 million people in South Florida live along the coast. And unlike many cities, where the wealth congregates in the hills, southern Florida’s most valuable real estate is right on the water.

{ Rolling Stones | Continue reading }

related { Global warming has slowed. The rate of warming of over the past 15 years has been lower than that of the preceding 20 years. There is no serious doubt that our planet continues to heat, but it has heated less than most climate scientists had predicted. | The Economist }

Hurricane Sandy was the largest storm to hit the northeast U.S. in recorded history, killing 159, knocking out power to millions, and causing $70 billion in damage in eight states. Sandy also put the vulnerability of critical infrastructure in stark relief by paralyzing subways, trains, road and air traffic, flooding hospitals, crippling electrical substations, and shutting down power and water to tens of millions of people. But one of the larger infrastructure failures is less appreciated: sewage overflow.

Six months after Sandy, data from the eight hardest hit states shows that 11 billion gallons of untreated and partially treated sewage flowed into rivers, bays, canals, and in some cases, city streets, largely as a result of record storm-surge flooding that swamped the region’s major sewage treatment facilities. To put that in perspective, 11 billion gallons is equal to New York’s Central Park stacked 41 feet high with sewage, or more than 50 times the BP Deepwater Horizon oil spill. The vast majority of that sewage flowed into the waters of New York City and northern New Jersey in the days and weeks during and after the storm.

{ Climate Central | PDF }

{ Thanks Tim }