• Scientists show how a hot, steamy afternoon kills the chill on a beer can

    A video from the University of Washington explains how condensation heats up frosty cans more quickly.

    By Alan Boyle, Science Editor, NBC News


    Droplets of condensation may make a cold can of beer look more appealing on a hot day, but they're also making that frosty brew warm up faster. So here's some news you can use: If it's hot and humid, put a cover over your can of cold beverage. And if you want to warm up a frozen can quickly, don't bake it. Steam it.

    That's exactly what University of Washington researchers did in a series of experiments to show how the warming power of condensation applies to issues ranging from colder beer to hotter climates.

    The beer-can study, published in the April issue of Physics Today, began a couple of years ago when UW atmospheric scientist Dale Durran was looking for a way to explain how condensation produced heat as the flip side of evaporative cooling. The cooling effect is well-known — we feel it when sweat evaporates to cool us off in the summer time, or when we turn on a mist cooler. But the flip side of the effect is less widely understood.

    Durran figured out that the condensation on a cold aluminum can might serve as a handy illustration. He did a quick back-of-the-napkin calculation, and found that the heat released by water just 100 microns (four thousandths of an inch) thick should heat its contents by 9 degrees Fahrenheit (5 degrees Celsius).

    "I was surprised to think that such a tiny film of water would cause that much warming," Durran said in a UW news release.

    He recruited a fellow atmospheric scientist at UW, Dargan Frierson, to conduct the initial experiment ... in Frierson's basement bathroom. First, they set a can of beverage on the toilet tank and warmed it up with a space heater. Then they took another can, turned on the shower and let the bathroom get nice and steamy. Each time they ran the experiment, the researchers stuck a thermometer through the can's pop-top opening and watched the temperature rise over the course of 15 minutes.

    Mariusz Kaldon

    Droplets of condensation on a chilly can are a signal that the temperature inside is rising.

    Frierson said conditions got a little sticky in the steamed-up bathroom. "I think that's the most uncomfortable my research has ever made me — but it's all for science," he told NBC News.

    Even though the air temperature was the same in both cases, the liquid in the steamed-up can warmed up twice as fast. The researchers followed up on the basement-bathroom findings with more rigorous lab experiments. Every time, the cans warmed up more quickly in more humid conditions.

    The researchers even charted how quickly 12-ounce aluminum cans of chilled liquid should warm up, depending on different levels of temperature and humidity. For example, in five minutes, the can should get 6 degrees F (3 degrees C) warmer due to condensation amid New Orleans' typical summer conditions. The equivalent warm-up factor would be 3.5 degrees F (2 degrees C) in New York, and 2 degrees F (1 degree C) in Seattle. But in Dhahran, a Saudi city that ranks among the hottest, stickiest places in the world, the can would get about 14 degrees F (8 degrees C) warmer in five minutes.

    That's why covering a cold can is a such a good idea on a steamy-hot summer day. "Probably the most important thing a beer koozie does is not simply insulate the can, but keep condensation from forming on the outside of it," Durran said.

    The effects of condensation and evaporation are well-known to climatologists, but Durran and Frierson say the beer-can experiments can give the general public a better understanding of atmospheric dynamics.

    "Condensation as a heat source is just tremendously important," Frierson said. "It's really like the gasoline that powers hurricanes, thunderstorms and tornadoes."

    Some climate models suggest that there could be 25 percent more humidity in the atmosphere by the end of the 21st century, and that could lead to more bouts of extreme weather in the decades to come.

    "We want people to appreciate how powerful this effect is," Durran told NBC News. "A very thin film around the can makes a big difference in the temperature of its contents, and that just makes you appreciate the importance of that same heating effect in our atmosphere."

    Here's how to run the experiment described in the YouTube video from University of Washington Department of Atmospheric Sciences Outreach:

    1. Freeze two cans of your favorite beverage. This should take roughly seven hours, depending on your freezer.
    2. Fifteen minutes before taking out the cans, preheat oven to 250 degrees F and start boiling water in a pot. Place a cookie rack on top of pot.
    3. Take the cans out of freezer. Place one in the preheated oven. and one over the boiling pot. 
    4. Start timer for 10 minutes. 
    5. After 10 minutes, carefully remove cans from oven and pot.
    6. Crack open both cans and pour into separate glasses.
    7. Take a photo/video of the two cans and glasses, go to the UW YouTube page, and post a video response.

    More beer-can science:

    Update for 9:30 p.m. ET April 26: Would wiping off the drops of condensation keep your drink cooler? Sorry, says UW spokeswoman Hannah Hickey. "That will only make your drink even warmer," she writes in a Twitter update.

    Update for 2:25 p.m. ET April 27: Some commenters are wondering why there's so much fuss over a relatively simple concept. The point of the exercise wasn't really to break new ground in atmospheric physics (or in summertime beverage consumption), but "to improve our intuition about the power of condensational heating" — which is a huge factor in climate dynamics. Durran explained further in a comment below, and I'm providing an extended version of his comments here to give them a little more visibility:

    "In my class, students definitely need to know how condensation causes heating. Here's how. There are bonds that link water molecules together into a crystal lattice to form ice. It takes heat (energy) to break a few of those bonds and turn ice to liquid water. To evaporate the liquid water, the rest of the bonds between molecules need to be broken, which takes a lot more heat. Once all the bonds are broken, the liquid is converted to water vapor, an invisible gas.

    "This processes reverses when water vapor is cooled enough to condense as liquid water. Bonds between molecules re-form, and the heat it took to originally break them is released into the surroundings.

    "The reason we make a big deal about the power of condensational heating is that it does amazing things in the atmosphere, such as powering the updrafts in thunderstorms. The rising cloud-filled updrafts in the video linked below ascend like hot-air balloons because they are warmed, not by burning a fuel like propane, but by the heat released as water vapor condenses.

    "Here's the video link: http://www.youtube.com/watch?v=GVIwDoogncQ

    "Such a visualization might help people understand some of the applications. (Only the last half of the Physics Today article was about the beer can heating.)"

    Durran and Frierson are the authors of "Condensation, Atmospheric Motion, and Cold Beer" in Physics Today. Supplemental experiments are described in "An Experiment Uses Cold Beverages to Demonstrate the Warming Power of Latent Heat." Lab experiments were performed by Stella Choi and Steven Brey. Galen Richards and Jaycyl Golding, high school students serving as Pacific Science Center Discovery Corps interns, worked on earlier versions of the experiments. Instrument makers Allen Hart and Steven Domonkos built experimental apparatuses. Funding was provided by National Science Foundation grants AGS-0846641 and AGS-1138977.

    Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

  • Hot cities more sustainable than cold ones, study says

    Reuters file

    A woman walks her dog in Minneapolis. Indoor energy demands in the chilly city are higher than cooling demands in Miami, according to a new study.

    By John Roach, Contributing Writer, NBC News

    When it's hot outside, people crank up air conditioners that usually suck electricity from coal- and natural gas-fired power plants at the root of human-caused global warming. This seems like a recipe for disaster, but it's more sustainable than living in a cold climate and cranking up the heat, a new paper suggests.

    "The traditional view that living in hot desert areas is not sustainable should be re-examined," Michael Sivak, a research professor at the University of Michigan, Ann Arbor, told NBC News. "Because my data suggest that from this point of view — mainly a climate control point of view — living in very cold areas is less sustainable than hot areas."

    He compared the energy demands for indoor heating and cooling in Minneapolis, Minn., the coldest metropolitan area in the country, with those in Miami, Fla., the warmest big city. He found the demands are 3.5 times greater in Minnesota.

    The biggest factor in his comparison is the number of heating or cooling days per year, which reflects the demand for energy needed to heat or cool a building. The measure is calculated by comparing the mean daily outdoor temperature with 18 degrees Celsius (64.4 degree Fahrenheit). So, for example, a 10 degree Celsius day corresponds to 8 heating degree days. A 25 degree Celsius day corresponds to 7 cooling degree days. In earlier research, Sivak found that Minneapolis has 4,376 heating degree days and Miami has 2,423 cooling degree days per year.

    "The need for heating in Minneapolis is more energy demanding than cooling in Miami because the difference of the ambient temperature from the desired temperature is greater in Minneapolis than in Miami," Sivak explained.

    His comparison also included:

    • the efficiencies of heating and cooling appliances (a typical air conditioner is about four times more energy efficient than a typical furnace or boiler primarily because it takes more energy to heat up a room than it does to cool it); 
    • and the efficiencies of power plants, which generate nearly all the electricity used in cooling and 7 percent for heating. ("In terms of power plant efficiencies, cooling is worse than heating," he noted). 

    When all three parameters are taken into consideration, including cooling days in Minnesota and heating days in Miami, Sivak found that Minneapolis is 3.5 times as energy-demanding as Miami.

    The study doesn't examine what happens as the planet warms, and thus fewer heating days are needed in places such as Minnesota, Buffalo, N.Y., and Portland, Ore., and more cooling days are required in Miami, Phoenix and Las Vegas, but the finding may be a silver lining of global warming.

    "Proportionately, you would be shifting the needs," Sivak said. "You would be heating less and you would be cooling more."

    In fact, he noted in a paper published Wednesday in Environmental Research Letters, the impact of warm-city living may be even more pronounced than suggested by his calculations since "people are generally more tolerant of heat than of cold."

    In other words, people are more likely to turn on their heater when there's a nip in the air than they are their AC when the temperatures begin to rise.

    While all of this sounds reasonable, "you run up against basic physical constraints in a hot place that you don't in a cold place," Austin Troy, director of the transportation research center at the University of Vermont, told NBC News. Troy is also the author of The Very Hungry City, a book that illustrates the energy demands of living in warm climates.

    For example, in a cold place you can build an passive solar house that uses very little energy to heat it, but similar options are lacking for people living in hot climates. And as the climate warms, in the "sun belt there'll be significantly increased cooling demands for the summer," he added.

    John Roach is a contributing writer for NBC News. To learn more about him, visit his website. 

  • Arctic gets greener as climate warms up

    NASA's Goddard Space Flight Center Scientific Visualization Studio

    Of the 10 million square miles (26 million square kilometers) of northern vegetated lands, 34 to 41 percent showed increases in plant growth (green and blue), 3 to 5 percent decreases in plant growth (orange and red), and 51 to 62 percent no changes (yellow) over the past 30 years, new research shows.

    By LiveScience

    Higher temperatures and a longer growing season mean some of Earth's chilliest regions are looking increasingly green, researchers say.

    Today, the plant life at northern latitudes often looks like the vegetation researchers would have observed up to 430 miles (700 kilometers) farther south in 1982, according to a new study.

    "It's like Winnipeg, Manitoba, moving to Minneapolis-Saint Paul in only 30 years," study researcher Compton Tucker of NASA's Goddard Space Flight Center in Greenbelt, Md., said in a statement.

    Tucker and a team of university and NASA scientists looked at 30 years' worth of satellite and land surface data on vegetation growth from 45 degrees north latitude to the Arctic Ocean. In this region, large patches of lush vegetation now stretch over an area about the size of the continental United States and resemble what was found 4 to 6 latitude degrees to the south in 1982, the researchers say.

    "Higher northern latitudes are getting warmer, Arctic sea ice and the duration of snow cover are diminishing, the growing season is getting longer and plants are growing more," climate scientist Ranga Myneni of Boston University said in a statement, adding that the changes are leading to great disruptions for the region's ecosystems. [10 Facts About Arctic Sea Ice]

    The Arctic has been warming at a faster rate than the rest of the world in the past several decades, and Myneni says an amplified greenhouse effect is largely to blame for the changes in plant life. In this cycle, high concentrations of heat-trapping gasses drive up temperatures in the ocean and atmosphere. This warming cuts down Arctic sea ice and snow cover, causing the oceans and land surfaces in the region to be exposed (ice and snow are more reflective than darker surfaces); these surfaces absorb more heat from the sun's rays, which leads to further heating of the air and further reduction of sea ice and snow. Myneni warns that the cycle could get worse.

    "The greenhouse effect could be further amplified in the future as soils in the north thaw, releasing potentially significant amounts of carbon dioxide and methane," Myneni said.

    Using climate models, the team found that Arctic and boreal regions could see the equivalent of a 20-degree latitude shift by the end of this century due to rising temperatures. But this doesn't necessarily mean more and more plants. The researchers say the amplified greenhouse effect could have other consequences, like more forest fires, pest infestations and droughts, which cut vegetation growth.

    And the availability of water and sunlight determines where plants will thrive. "Satellite data identify areas in the boreal zone that are warmer and dryer and other areas that are warmer and wetter," Ramakrishna Nemani of NASA's Ames Research Center in Moffett Field, Calif., explained in a statement. "Only the warmer and wetter areas support more growth."

    The researchers also saw more plant growth in the boreal zone from 1982 to 1992 than from 1992 to 2011 — a trend they attributed to a lack of water in the region during the last two decades of the study.

    The research was detailed Sunday in the journal Nature Climate Change.

    Follow LiveScience on Twitter @livescience. We're also on Facebook and Google+.

    Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

  • Captured deep beneath the waves: Giant squid filmed in natural habitat

    Scientists say they have captured video of a giant squid in its natural habitat deep in the ocean for the first time. NBCNews.com's Dara Brown reports.

    By Arata Yamamoto and Peter Jeary, NBC News

    The world's first moving images of a giant squid living in its natural habitat have been captured by a team of scientists more than half a mile below the surface of the Pacific Ocean.

    The ghostly pictures of the 10-foot-long giant squid were recorded from a state-of–the-art submersible carrying a three-person team of Japanese zoologist Tsunemi Kubodera, a camera operator and the submersible’s pilot, who made around 100 dives during an expedition last summer.

    Although small by giant squid standards – the largest ever caught measured 59 feet – it was the first time a live giant squid had been caught on video deep in the ocean.

    Kubodera, from Japan's National Museum of Nature and Science, credited the success to the submersible’s silence and hi-tech lighting.

    "A giant squid would never appear before a pool of light, that possibility is extremely slim", he told NBC News. "That's why we had to use lights that they wouldn't be able to detect. In fact, they're lights even humans wouldn't be able to see either."

    “If you try to approach making a lot of noise, using bright lights, then the squid won't come anywhere near you," he added. “So we sat there in the pitch black, using a near-infrared light invisible even to the human eye, waiting for the giant to approach.''

    'It was stunning'
    On one dive in July 2012, near the Ogasawara islands, 620 miles south of Tokyo, they finally had their close encounter more than 2,000 feet down and followed the creature even deeper.

    “This was the first time for me to see with my own eyes a giant squid swimming,'' Kubodera said. “It was stunning. I couldn't have dreamt that it would be so beautiful. It was such a wonderful creature.”

    NHK/NEP/Discovery Channel via Reuters

    A giant squid is seen in this video still talken near the Ogasawara Islands in July 2012.

    The squid was missing its characteristic two longest tentacles – and scientists don’t know why. Marine biologists said if that pair of tentacles had been intact, the creature would probably have measured up to 23 feet long.

    Kubodera’s deep-sea expedition was the culmination of a 10-year project by Japanese broadcaster NHK to capture pictures of the mysterious creature in its habitat. An  ultra-sensitive high-definition camera was developed to operate at the ocean depths, using special light that was invisible to the sensitive eyes of the giant squid.

    NHK will air its video footage in Japan in a prime-time documentary entitled "Legends of the Deep: Giant Squid" on Jan. 13. It will also be shown on the Discovery Channel on Jan.  27.

    Reuters contributed to this report.

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  • 'Horrible' sea level rise of more than 3 feet plausible by 2100, experts say

    Alister Doyle / Reuters file

    Experts increasingly recognize that ice melting in Antarctica could push up sea levels dramatically higher in coming decades.

    By John Roach, NBC News

    Melting glaciers in Antarctica and Greenland may push up global sea levels more than 3 feet by the end of this century, according to a scientific poll of experts that brings a degree of clarity to a murky and controversial slice of climate science. 

    Such a rise in the seas would displace millions of people from low-lying countries such as Bangladesh, swamp atolls in the Pacific Ocean, cause dikes in Holland to fail, and cost coastal mega-cities from New York to Tokyo billions of dollars for construction of sea walls and other infrastructure to combat the tides.

    "The consequences are horrible," Jonathan Bamber, a glaciologist at the University of Bristol and a co-author of the study published Jan. 6 in the journal Nature Climate Change, told NBC News. 

    Estimating how much sea levels will rise from ice sheet melting is one of the more challenging aspects of climate science. Some evidence suggests recent accelerated melting is related to changes in ocean and atmospheric temperature, though natural variability may play an important role.

    In addition, glaciers respond to external forces such as warmer temperatures in different ways, even when they are located right next to each other. As a result, there is tremendous uncertainty in the scientific community over how the melting will affect sea levels over the next century.

    Bamber and colleague Willy Aspinall attempted to find clarity in the chaos using a scientific polling technique common in fields such as predicting earthquakes and volcanic eruptions, but until now not applied to climate science.

    The pair sent 26 of the world's leading glaciologists a series of questions about the behavior of the Antarctic and Greenland ice sheets. About half replied to the survey in 2010. The respondents were polled again in 2012 to assess the robustness of their answers.

    Bamber said this type of approach is "a lot more than an opinion poll." The experts were handpicked to get a representative perspective of world leaders from the ice sheet modeling and observational fields. "We analyzed the results in a very systematic, rigorous, and statistically robust way," he added.

    The median estimate from the experts is that the melting ice sheets will contribute 1 foot (29 centimeters) to sea level rise by the year 2100 with a 5 percent chance their contribution could exceed 2.8 feet (84 centimeters). When the effect of thermal expansion (water expands as it warms) is taken into account, the high-end estimate is more than 3 feet (1 meter).

    The estimates are higher than the controversial figures in the 2007 report  from the Intergovernmental Panel on Climate Change (IPCC) of up to 23 inches (59 centimeters) and higher than the unpublished estimates being prepared for the next IPCC report, said Bamber, who is a review editor for that document and has seen the estimates.

    The discrepancy likely reflects added weight given to recent studies that indicate glacier melt has accelerated in recent years in Antarctica and Greenland, and that the West Antarctic ice sheet could partially collapse by the end of this century.

    "The numbers we are getting out of our elicitation reflect the fact that the world leaders in this field are now cognizant of the fact that the ice sheets are quite responsive and, in particular, there is a potential for them to make a really quite dramatic contribution," Bamber said.

    The greatest drama would be a more than 3-foot rise in sea levels from the combined effect of melting ice and thermal expansion, which the study indicates has a 1 in 20 chance of occurring. 

    How much of this drama can be attributed to human burning of fossil fuels, the study indicates, remains murky. “There is really no consensus amongst the experts we approached,” Bamber said. “That’s something that we in the scientific community need to address as a matter of urgency.”

    John Roach is a contributing writer for NBC News Digital. To learn more about him, check out his website.