Tag Archives: water

Volleyball Sized Hail

photo of volleyball sized hail

On July 23, 2010, a severe thunderstorm struck Vivian, South Dakota, USA, a quiet rural community of less than 200. While there was nothing unusual about a violent summer storm, the softball (and larger)-sized hail that accompanied it was extraordinary. In fact, it led to the discovery of the largest hailstone ever recorded in the United States.

Once the thunderstorm passed, Vivian resident Les Scott ventured outside to see if there was any damage as a result of the storm. He was surprised to see a tremendous number of large hailstones on the ground, including one about the size of a volleyball. Scott gathered up that stone, along with a few smaller ones, and placed them in his freezer.

How does hail form?

Inside of a thunderstorm are strong updrafts of warm air and downdrafts of cold air.
If a water droplet is picked up by the updrafts…it can be carried well into colder zones and the water droplet freezes.
As the frozen droplet begins to fall, carried by cold downdrafts, it may partially thaw as it moves into warmer air toward the bottom of the thunderstorm
But, if the little half-frozen droplet get picked up again by another updraft and is carried back into very cold air it will re-freeze. With each trip above and below the freezing level our frozen droplet adds another layer of ice.
Finally, the frozen hail, with many layers of ice, much like the rings in a tree falls to the ground.

According to NOAA, the Kansas City hail storm on April 10, 2001 was the costliest hail storm in the U.S. which caused damages of an estimated $2 billion.

Image from NOAA

Critter Cam: Sea Lion versus Octopus

Octopus vs. Sea Lion – First Ever Video

Sea lions fitted with GPS trackers and a National Geographic Crittercam are taking scientists on amazing journeys to previously unknown marine ‘hot spots.’ These areas are important not only for providing the sea lions’ food, but also for maintaining fish populations.

The Crittercams were deployed at Dangerous Reef in Spencer Gulf, a rocky island the size of a football field, and home to the biggest Australian sea lion colony.
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Dr. Page says, “One important discovery is that the sea lions always feed on the sea floor” and they don’t eat open ocean fish, known as pelagic. “This is critical information because the marine parks are being set up to protect sea floor habitats,” a move that the scientists can now confirm will protect critical sea lion resources.

In one of the more spectacular pieces of Crittercam video so far, we can see this female working hard to handle a challenging prey item – a large octopus. Too big to swallow in one gulp, she drags it to the surface where she can breathe while she works at breaking it down into bite-size pieces.

Solar-Powered Desalination

Saudi Arabia meets much of its drinking water needs by removing salt and other minerals from seawater. Now the country plans to use one of its most abundant resources to counter its fresh-water shortage: sunshine.
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KACST’s main goal is to reduce the cost of desalinating water. Half of the operating cost of a desalination plant currently comes from energy use, and most current plants run on fossil fuels.
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Reducing cost isn’t the only reason that people have dreamed of coupling renewable energy with desalination for decades, says Lisa Henthorne, a director at the International Desalination Association. “Anything we can do to lower this cost over time or reduce the greenhouse gas emissions associated with that power is a good thing,” Henthorne says. “This is truly a demonstration in order to work out the bugs, to see if the technologies can work well together.”
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Saudi Arabia, the top desalinated water producer in the world, uses 1.5 million barrels of oil per day at its plants, according to Arab News.
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In a concentrated PV system, lenses or mirrors focus sunlight on ultra-efficient solar cells that convert the light into electricity. The idea is to cut costs by using fewer semiconductor solar cell materials. But multiplying the sun’s power by hundreds of times creates a lot of heat. “If you don’t cool [the device], you end up overheating the circuits and killing them,” says Sharon Nunes, vice president of IBM Big Green Innovations. IBM’s solution is to use a highly conducting liquid metal–an indium gallium alloy–on the underside of silicon computer chips to ferry heat away. Using this liquid metal, the researchers have been able to concentrate 2,300 times the sun’s power onto a one-square-centimeter solar device. That is three times higher than what’s possible with current concentrator systems, says Nunes.

Finding good desalination solution could help many other locations (including southern California). But there is still a long way to go.

Why Wasn’t the Earth Covered in Ice 4 Billion Years Ago – When the Sun was Dimmer

Climate scientists from all over the globe are now able to test their climate models under extreme conditions thanks to Professor Minik Rosing, University of Copenhagen. Rosing has solved one of the great mysteries and paradoxes of our geological past, namely, “Why the earth’s surface was not just one big lump of ice four billion years ago when the Sun’s radiation was much weaker than it is today.” Until now, scientists have presumed that the earth’s atmosphere back then consisted of 30% carbon dioxide (CO2) which ensconced the planet in a protective membrane, thereby trapping heat like a greenhouse.

The faint early sun paradox
In 1972, the late, world famous astronomer Carl Sagan and his colleague George Mullen formulated “The faint early sun paradox. ” The paradox consisted in that the earth’s climate has been fairly constant during almost four of the four and a half billion years that the planet has been in existence, and this despite the fact that radiation from the sun has increased by 25-30 percent.

The paradoxical question that arose for scientists in this connection was why the earth’s surface at its fragile beginning was not covered by ice, seeing that the sun’s rays were much fainter than they are today. Science found one probable answer in 1993, which was proffered by the American atmospheric scientist, Jim Kasting. He performed theoretical calculations that showed that 30% of the earth’s atmosphere four billion years ago consisted of CO2. This in turn entailed that the large amount of greenhouse gases layered themselves as a protective greenhouse around the planet, thereby preventing the oceans from freezing over.

Mystery solved
Now, however, Professor Minik Rosing, from the Natural History Museum of Denmark, and Christian Bjerrum, from the Department of Geography and Geology at University of Copenhagen, together with American colleagues from Stanford University in California have discovered the reason for “the missing ice age” back then, thereby solving the sun paradox, which has haunted scientific circles for more than forty years.

Professor Minik Rosing explains, “What prevented an ice age back then was not high CO2 concentration in the atmosphere, but the fact that the cloud layer was much thinner than it is today. In addition to this, the earth’s surface was covered by water. This meant that the sun’s rays could warm the oceans unobstructed, which in turn could layer the heat, thereby preventing the earth’s watery surface from freezing into ice. The reason for the lack of clouds back in earth’s childhood can be explained by the process by which clouds form. This process requires chemical substances that are produced by algae and plants, which did not exist at the time. These chemical processes would have been able to form a dense layer of clouds, which in turn would have reflected the sun’s rays, throwing them back into the cosmos and thereby preventing the warming of earth’s oceans. Scientists have formerly used the relationship between the radiation from the sun and earth’s surface temperature to calculate that earth ought to have been in a deep freeze during three billion of its four and a half billion years of existence. Sagan and Mullen brought attention to the paradox between these theoretical calculations and geological reality by the fact that the oceans had not frozen. This paradox of having a faint sun and ice-free oceans has now been solved.”

CO2 history iluminated
Minik Rosing and his team have by analyzing samples of 3.8-billion-year-old mountain rock from the world’s oldest bedrock, Isua, in western Greenland, solved the “paradox”.

But more importantly, the analyses also provided a finding for a highly important issue in today’s climate research – and climate debate, not least: whether the atmosphere’s CO2 concentration throughout earth’s history has fluctuated strongly or been fairly stable over the course of billions of years.

“The analyses of the CO2-content in the atmosphere, which can be deduced from the age-old Isua rock, show that the atmosphere at the time contained a maximum of one part per thousand of this greenhouse gas. This was three to four times more than the atmosphere’s CO2-content today. However, not anywhere in the range of the of the 30 percent share in early earth history, which has hitherto been the theoretical calculation. Hence we may conclude that the atmosphere’s CO2-content has not changed substantially through the billions of years of earth’s geological history. However, today the graph is turning upward. Not least due to the emissions from fossil fuels used by humans. Therefore it is vital to determine the geological and atmospheric premises for the prehistoric past in order to understand the present, not to mention the future, in what pertains to the design of climate models and calculations,” underscores Minik Rosing.

Full press release from the University of Copenhagen in Denmark.

Researchers Explain How Rotifers Thrive Despite Forgoing Sex

Bdelloid rotifers haven’t had sex for at least thirty million years. Most asexual animals are doomed to extinction. The excellent show, Science Friday, looks at the extraordinary adaptations that allow rotifers to thrive sex-free.

For millions of years, the rotifers have reproduced asexually, flying in the face of an idea known as the Red Queen Hypothesis, which states that without the advantage of sexual reproduction, more-rapidly evolving parasites and predators will eventually doom the asexual species. Now, the researchers studying the tiny organism say that its ability to dry up and blow away to greener pastures may have given the rotifers a hidden tactical edge in this evolutionary war.

The webcast provides a nice overview of the research. Every week Science Friday provides many such interesting reviews of recent scientific research.

What Are Rotifers?

Rotifers are small, mostly freshwater animals, and are amongst the smallest members of the Metazoa — that group of multicellular animals which includes humans, and whose bodies are organized into systems of organs.
Most rotifers are about 0.5mm in length or less, and their bodies have a total of around a thousand cells. This means that their organ systems are a greatly simplified distillation of the organ systems found in the bodies of the higher animals.

A typical rotifer might have a brain of perhaps fifteen cells with associated nerves and ganglia, a stomach of much the same number, an excretory system of only a dozen or so cells, and a similarly fundamental reproductive system. They have no circulatory system. It is an anomaly that despite their complexity, many rotifers are much smaller than common single-celled organisms whose world they share.
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they are able to survive long periods — even perhaps hundreds of years — in a dried or frozen state, and will resume normal behaviour when rehydrated or thawed.
Secondly, they exhibit what biologists call cell constancy — they grow in size not by cell division, but by increase in the size of the cells which they already have.

Dolphin Delivers Deviously for Rewards

Deep thinkers

At the Institute for Marine Mammal Studies in Mississippi, Kelly the dolphin has built up quite a reputation. All the dolphins at the institute are trained to hold onto any litter that falls into their pools until they see a trainer, when they can trade the litter for fish. In this way, the dolphins help to keep their pools clean.

Kelly has taken this task one step further. When people drop paper into the water she hides it under a rock at the bottom of the pool. The next time a trainer passes, she goes down to the rock and tears off a piece of paper to give to the trainer. After a fish reward, she goes back down, tears off another piece of paper, gets another fish, and so on. This behaviour is interesting because it shows that Kelly has a sense of the future and delays gratification. She has realised that a big piece of paper gets the same reward as a small piece and so delivers only small pieces to keep the extra food coming. She has, in effect, trained the humans.

Her cunning has not stopped there. One day, when a gull flew into her pool, she grabbed it, waited for the trainers and then gave it to them. It was a large bird and so the trainers gave her lots of fish. This seemed to give Kelly a new idea. The next time she was fed, instead of eating the last fish, she took it to the bottom of the pool and hid it under the rock where she had been hiding the paper. When no trainers were present, she brought the fish to the surface and used it to lure the gulls, which she would catch to get even more fish. After mastering this lucrative strategy, she taught her calf, who taught other calves, and so gull-baiting has become a hot game among the dolphins…

Too bad for the poor gulls but this is pretty cool. Plus it serves gulls right, one stole my breakfast a few years ago when I was down in Florida.

Appropriate Technology: Solar Water in Poor Cairo Neighborhoods

Cairo Slums Get Energy Makeover

Since 2003 the nonprofit Solar CITIES project has installed 34 solar-powered hot water systems and 5 biogas reactors in Cairo’s poor Coptic Christian and Islamic neighborhoods.
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Solar CITIES’ hot water systems are constructed from recycled materials and are uniquely tailored to the parts of a city where water and electricity availability are often sporadic. “The problem with professional solar hot water systems is that they’re made for cities with continuous water,” Culhane said. By contrast, Solar CITIES’s water heaters use a city’s water when it’s available but draw from a backup storage tank when it’s not.

The setup consists of an insulated rectangular box covered in clear glass or plastic on one side. Inside the box are copper tubes wrapped in sheets of aluminum, which are painted black. Sunlight striking the darkened aluminum is converted to heat, which is then used to warm water flowing through the pipes. The glass sheet on top of the box prevents the heat from being carried away by wind.
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Solar CITIES also installs biogas reactors, which are based on designs Culhane saw while working in India. The reactors use microbes harvested from animal guts to break down food wastes into flammable gas that can be used for cooking and heating. If necessary, the reactors can draw hot water from the solar water heaters to maintain the warm temperatures the bacteria need to survive.

By attaching a simple plastic tube to the reactors, gas can be piped down several stories for residents to use. “In 24 hours, you’ve got 2 hours of cooking gas from yesterday’s cooking garbage,” Culhane said. The biogas reactors provide a more reliable supply of cooking gas than most residents currently have.

Awesome, I love to see people using engineering to make life better for those that can truly use help.

Washing Machine Uses 90% Less Water

We wrote about the nearly waterless washing machine from Xeros previously, here are some additional details. The nearly waterless washing machine (which uses 90% less water) was developed by transferring known science to another application. After extensive R&D by University of Leeds scientists a nylon polymer was selected to absorb stains and dirt due to its unique property to become highly absorbent in humid conditions. Better still, it is highly resilient so can be re-used time after time without losing its strength.

The power of polymer cleaning
The nylon polymer has an inherent polarity that attracts stains. Think of how your white nylon garments can get dingy over time as dirt builds up on the surface despite constant washing. However, under humid conditions, the polymer changes and becomes absorbent. Dirt is not just attracted to the surface, it is absorbed into the center.

Such research in university settings, then transferred to products are a great source of economic growth and environmental improvement.

Sustainable Aquaculture

Located on an island in the Guadalquivir river, 10 miles (16km) inland from the Atlantic, Veta la Palma produces 1,200 tons of sea bass, bream, red mullet and shrimp each year. Yet unlike most of the world’s fish farms, it does so not by interfering with nature, but by improving upon it. “Veta la Palma raises fish sustainably and promotes the conservation of birdlife at the same time,” says Daniel Lee, best practices director for the U.S.-based Global Aquaculture Alliance. “I’ve never seen anything quite like it.”

With wild fish stocks declining precipitously around the globe, thanks to overfishing and climate change, aquaculture has emerged as perhaps the only viable way to satisfy the world’s appetite for fish fingers and maki rolls. In the next few years, consumption of farm-raised fish will surpass that caught in the wild for the first time, according to the United Nations Food and Agriculture Organization. But most fish farms — even ones heralded as “sustainable” — create as many problems as they solve, from fecal contamination to the threat that escaped cultivated fish pose to the gene pool of their wild cousins.

Veta la Palama is different. In 1982, the family that owns the Spanish food conglomerate Hisaparroz bought wetlands that had been drained for cattle-farming and reflooded them. “They used the same channels built originally to empty water into the Atlantic,” explains Medialdea. “Just reversed the flow.” Today, that neat little feat of engineering allows the tides to sweep in estuary water, which a pumping station distributes throughout the farm’s 45 ponds. Because it comes directly from the ocean, that water teems with microalgae and tiny translucent shrimp, which provide natural food for the fish that Veta la Palma raises.

By hewing as closely as possible to nature, the farm avoids many of the problems that that plague other aquaculture projects. Low density — roughly 9 lb. (4 kg) of fish to every 35 cu. ft. (1 cu m) of water — helps keep the fish free of parasites (the farm loses only 0.5% of its annual yield to them). And the abundant plant life circling each pond acts as a filter, cleansing the water of nitrogen and phosphates.

Friday Fun: Dolphins Play with Air Bubble Rings

Bubbles in water

The bubble is the most stable situation for an amount of gas phase in water (liquid phase). A surface tension is associated with the surface between the gas phase and the liquid phase, the surface tension tends to minimize the surface area. This is also described in the section on bubbles in bubble models. Given a volume of gas, the sphere (bubble) shape is the shape that has the smallest surface area with respect to the containing volume.

The situation of a bubble in water is comparable to a balloon. The balloon surface is elastic. The tension of it tries to minimize the surface: if you don’t tie a knot in the balloon after blowing it up, air escapes and the surface of the balloon is minimized to the initial unstretched situation.
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Bubbles do not turn into rings naturally. Something has to be done for that. However, they have long lives and often make it up to the surface. Hence they are stable structures.
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Dolphins create bubble rings by blowing air in a water vortex ring: by flipping a fin they create a vortex ring of water. The then blow air in the ring, which goes to the center of the vortex ring. In the water vortex ring the natural location of the air is in the center of the vortex. When air and water move in a circular path like they do in the vortex ring, air and water are separated due to the centripetal force. Since density of water is larger than air, water moves at the outside, while the air ends up in the middle.

Follow the link for much more on the physics of bubble rings.