Sunday, November 18, 2012

New Home for the Visionlearning Blog

This blog is officially obsolete!  Find us at our new location:
http://www.visionlearning.com/blog/
Dear Readers,

We're excited to announce that the Visionlearning blog has moved to a new home on the main Visionlearning site.  We've got a new address and a new look, but we'll still be working hard to bring you interesting STEM and education posts, including:
In our new location, it will be easier than ever to access Visionlearning modules in disciplines from biology to physics, as well as our science glossary with hundreds of definitions of terms used in STEM disciplines.

We hope you'll join us in our new location -- http://www.visionlearning.com/blog/. To make sure you stay up to date, you can subscribe to receive new posts by email or RSS feed once you get there. We will not be maintaining this blog anymore, so please make sure you update your bookmarks, news readers, and other sources you use to find news and information.

As always, we would love to hear your thoughts on the new layout, the topics we're posting about, or any ways we can make the Visionlearning Blog better.  Thanks for reading!

Friday, November 9, 2012

Image of the Week: How to Look Inside a Fish

Scientists Sandra Raredon and Lynne Parenti at Smithsonian's National Museum of Natural History use
x-rays to get an inside look at fishes like these Lookdowns (Selene vomer).
Image courtesy: Smithsonian's National Museum of Natural History

Scientists use all sorts of visuals to study the natural world, including graphs, maps and photographs. But some of the most beautiful scientific visuals have to be the fish x-rays taken by Sandra Raredon and Lynne Parenti, ichthyologists (scientists who study fish) at Smithsonian's National Museum of Natural History.  Our image of the week is an x-ray showing three lookdowns (Selene vomer), silvery fish with a permanent "scowl" found mainly in warm waters of the western Atlantic.

The Smithsonian's fish collection contains about four million specimens, representing approximately 70 percent of the world's fish diversity, and Raredon and Parenti can study these specimens without having to dissect or otherwise damage them.  Their images help unravel the long history of fish evolution using clues, such as the number of vertebrae and positioning of fins, that are easily visible in x-rays.


LEARN MORE
Learn about how scientists use this technique and what they are learning from it on the Smithsonian National Museum of Natural History's exhibit page X-Ray Vision: Fish Inside Out.

Browse more of these beautiful x-rays on the NMNH Flickr page.

Learn about how visual data, whether x-rays or topographic maps, help scientists explore all kinds of topics in our module Data: Using Graphs and Visual Data.

Wednesday, November 7, 2012

Tragedies in Science: The Collapse of the Tacoma Narrows Bridge

Since it's collapse in 1940, the Tacoma Narrows
Bridge has been rebuilt, this time as a
twin suspension bridge. Image courtesy: WSDOT (Flickr CC)
When you think of iconic bridges of the world, the Tacoma Narrows Bridge, which spans a narrow strait in the Puget Sound south of Seattle, may not come to mind immediately.  But that bridge (today it's actually a set of twin bridges--one for each direction of traffic) has an incredible history that serves as a serious cautionary tale for engineers.

The original Tacoma Narrows bridge, completed in 1940, was a long time in the making but short-lived once it was finally built. The idea of building a bridge across the sound to connect the city of Tacoma to the Kitsap Peninsula dates back to at least 1889.  During the 1920s and 30s a number of citizen campaigns and leaders supported various designs and approaches to building a bridge

One of the major sticking points for all of these efforts was the cost. In 1938, the state of Washington applied for federal funding to build the bridge. The state bridge engineer, Clark Eldridge, drew up a fairly standard suspension bridge design with an estimated price tag of $11 million, but officials were skeptical that a project of that magnitude could pay for itself in bridge tolls.  In the end, they granted the state $6.4 million and required them to hire Leon Moisseiff, a bridge engineer from New York who said the bridge could be built for much less than $11 million.

Moisseff's plan was indeed much less expensive because his design used far less steel and called for the Tacoma Narrows Bridge to be very light and narrow compared to other suspension bridges of the time. When they saw the plan, engineers at the Washington State Highway Department protested, calling the bridge design "fundamentally unsound."  But that did not stop the project.  Construction began on November 23, 1938.

During construction, workers noticed that the bridge bounced.  Soon after opening in July 1940, the bridge became known by engineers and motorists alike for "the bounce" or "the ripple."  It was rated to withstand winds up to 120 miles per hour, but even in a light breeze the bridge moved.  Motorists reported waves, sometimes up to 5 feet tall, undulating from one end of the bridge to the other.  Sometimes the bouncing was short-lived, but on occasion it was reported to last for up to six hours. The bridge earned the nickname Galloping Gertie.  Some locals steered clear of Gertie out of fear or to avoid sea sickness; others sought it out as a thrill ride.

In the spring of 1940, the Toll Bridge Authority contacted Moisseiff who reported that two of his other recent bridges were having similar movement issues, but at a smaller scale. The Authority then hired engineering professor F. Bert Farquharson from the University of Washington to find a solution to the problem.  Farquharson and his students built scale models of the bridge and conducted wind tunnel experiments.  In October, engineers added temporary tie-down cables to anchor the bridge to the seafloor and diagonal cables between the bridge's deck and the main cables to brace it.  This helped limit the bridge's movement, but not enough.

In early November, as workers repaired one of the tie-down cables that had broken loose from Gertie's galloping, Farquharson completed his wind tunnel studies.  He noted a torsional (twisting) motion in the bridge model under high wind conditions.  "We watched it," Farquharson later told reporters, "and we said that if that sort of motion ever occurred on the real bridge, it would be the end of the bridge."

Guided by Farquharson's findings, the Toll Bridge Authority began drawing up a contract to have wind deflectors installed on the bridge. The morning of November 7, the state bridge engineer, Clark Eldridge was sketching plans for the deflectors, pricing materials, and preparing a rapid response that would have had the entire bridge covered in wind deflectors within 45 days. But they were too late.

By 7:30 am, 42-mile-per-hour winds were rushing up the Narrows from the Southwest and hitting Gertie broadside.  She began to gallop. Farquharson, Eldridge, and a crowd of spectators began to gather, photographing and even taking video of the bridge.  At 10:03 am, the bridge suddenly began the lateral twisting motion that Farquharson had feared.  Pieces of concrete from the roadway began to break free, and at 11:02 am, a 600-foot span collapsed into the sound.  Galloping Gertie had failed.


Footage from the Nov 7, 1940 collapse of the Tacoma Narrows Bridge. Courtesy: Internet Archives

Fortunately, no humans and only one dog died during the collapse, but the outcome could have easily been much worse.  In a situation like this who is to blame?  Did the collapse of the bridge result from an ethical breach or an honest miscalculation?  Does the designer of the bridge bear responsibility?  What about the federal officials who put construction costs above other considerations--including perhaps safety--when selecting a design and funding the project?

Answers to ethical questions like these are not always straightforward.  Fortunately, though, there are standards of conduct and general principles that members of the scientific community abide by.  You're probably familiar with the Hippocratic Oath that doctors take, declaring that (among other things) they vow to do no harm to their patients.  In the U.S., the National Society of Professional Engineers' code of ethics declares that engineers shall "hold paramount the safety, health and welfare of the public." General standards relating to scientific methods and to topics of study (especially human and animal subjects) also guide researchers.

So what if Clark Eldridge's original (more expensive) design had been built instead of Leon Moisseiff's lighter, cheaper version?  Structural engineers who reviewed the original plans for the State of Washington concluded that the bridge would likely still be standing.


LEARN MORE
For more about ethical standards and dilemmas in science and engineering, read our Scientific Ethics module.

For more about how models of all types are used in research, visit our module Research Methods: Modeling.

For more about the history and design of the Tacoma Narrows Bridge (and other suspension bridges), check out the Washington State Department of Transportation's More Than a Bridge site.

Friday, October 12, 2012

Image of the Week: Le Grand K of the Metric System

"Le Grand K," a cylindrical weight made of platinum and iridium that serves as the
international prototype of the kilogram, is kept in a vault in France.
Image: Bureau International des Poids et Mesures

In honor of National Metric Week (which wraps up tomorrow), our image of the week shows "Le Grand K," a cylindrical weight that is the international standard barer for the kilogram.  Made of platinum and iridium and created in 1889, this special weight literally defines the mass of a kilogram. There are six official copies held at the Bureau International des Poids et Mesures (International Bureau of Weights and Measures) and a number of other copies around the world that serve as the national standard for the kilogram in their home countries.

The kilogram is the only metric measurement that is still defined by a physical object, rather than a universal physical constant. (A meter, for example, used to have a platinum-iridium standard as well but is now defined as the distance that light travels in a vacuum in 1/299,792,458 of a second.)  In recent years, scientist have determined that Le Grand K is losing small amounts of mass, and some have been advocating for a new kilogram standard that is based on a physical constant.


LEARN MORE
Check out our module on the Metric System to learn more about the various metric units and how scientific notation helps us describe things that are very large or very small

Visit the Bureau International des Poids et Mesures to read more about the International Prototype for the Kilogram

Monday, October 8, 2012

Five Inspiring Hispanic Scientists

One of many inspiring Hispanic scientists: Dr. Helen
Rodriguez-Trias, physician, educator, and advocate
for women's health and equal access to medical.
care. Image Courtesy: National Library of Medicine
The U.S. Census Bureau estimates that the Hispanic population in the U.S. will reach 132.8 million (or 30 percent of the total U.S. population) by the year 2050.   But Hispanic students (as well as other minorities) continue to be underrepresented in the STEM disciplines and to receive STEM degrees at a lower rate than their White counterparts. In K-12 education, Hispanic students are more likely than Whites to be exposed to funding inequities and to have science teachers who did not major in science.

In the face of these disparities and in honor of National Hispanic Heritage Month, we're highlighting five Hispanic scientists that have had a major and lasting impact on the world around them.   In many cases they overcame obstacles, including racism and sexism, poverty, cultural and family expectations, and lack of mathematics background, in order to work and excel in the fields that they love.  Our hats are off to all of them, and to anyone out there who is studying or working in a STEM field.  May these stories inspire you.

Dr. Helen Rodriguez-Trias (1929 - 2001)
"We cannot achieve a healthier us without achieving a healthier, more equitable health care system, and ultimately, a more equitable society."

Helen Rodiriguez-Trias combined the two things she loved most--science and people--by pursuing a career in medicine. Born in New York city in 1929, Rodiriguez-Trias moved back and forth between New York and her parents' native Puerto Rico during her childhood and early career.  She graduated from the University of Puerto Rico Medical School in 1960 and established the island's first center for the care of newborn babies, which dramatically lowered the death rate for newborns at the hospital where she completed her residency.

In 1970, she moved back to New York where she became head of the pediatrics department at Lincoln Hospital in the South Bronx.  In addition to her work as a physician, Rodiriguez-Trias fought to improve medical care for people who had limited access due to poverty, cultural and language barriers, and discrimination. Among her many leadership roles, Rodiriguez-Trias served as the (first Latina) president of the American Public Health Association and the medical director of the New York State AIDS Institute. She also became a tireless advocate and leader in the women's health movement, fighting for equal access to healthcare for poor women and children and fighting against the horrifying practice of forced sterilization. In 2001, less than a year after receiving the Presidential Citizen's Medal, Helen Rodriguez-Trias succumbed to cancer.

For more, visit the National Library of Medicine and the American Journal of Public Health


Dr. Francisco Dallmeier (1953 - )
"In this century we will make the final decisions about how this sixth species extinction currently in progress will end… It is a tremendous responsibility."

At a very young age, Francisco Dallmeier knew that he wanted to follow in his great-grandfather's footsteps and make a career out of working with plants and animals.  At 14, he began volunteering at the La Salle Museum of Natural History in his hometown of Caracas, Venezuela.  He moved up the ranks with remarkable speed, and by age 20, he was appointed director of the museum.  At the same time, he was working toward a biology degree at the Central University of Venezuela, and he eventually moved to the United States to pursue a masters and then a Ph.D. in wildlife ecology at Colorado State University. 

From Colorado, Dallmeier went to Washington, DC to work at the Smithsonian Institution.  As the head of the Smithsonian's Monitoring and Assessment of Biodiversity (MAB) program, he has developed important and widely-recognized techniques for measuring and tracking changes in biodiversity. Dallmeier has worked all over the world in places as far reaching as Gabon and Peru focusing on ways to help environmental advocates and industry work together to reduce the impacts of human development.  MAB now has more than 300 research plots and trains scientists around the world in the tools and techniques of conservation biology.

For more, visit the Smithsonian Conservation Biology Institute and the Friends of the National Zoo


Ynes Mexia (1870-1938)
Ynes Mexia found her true passions--botany and exploring--a bit later in life.  The daughter of a Mexican diplomat and an American socialite, Mexia was born in Washington, DC in 1870.  She made her first career as a social worker, and it wasn't until age 51 that she began taking classes in botany at the University of California at Berkeley. In 1925, she joined a botanical collecting expedition to Mexico sponsored by Stanford University but decided to break off from the group to collect on her own.  She returned with more than 1,500 plant specimens, but that was only the beginning.

Mexia went on to conduct collecting expeditions (often solo) in Alaska, the western U.S., Mexico, and South America, including a 4,800-kilometer canoe trip along the Amazon River. During her last expedition to Mexico, she became ill and was diagnosed with lung cancer. She died in 1938 shortly after her diagnosis.  Mexia's career in botany was short, but her contribution was large: in 13 years of work she collected nearly 150,000 specimens.  Among those, roughly 500 were new species, and two were new genera.

For more, visit JSTOR Plant Science and the UC Berkeley Jepson Herbaria


Dr. Ellen Ochoa (1958 - )
As a child growing up in La Mesa, CA, Ellen Ochoa loved math and music.  She earned her undergraduate degree in physics from San Diego State University, and was contemplating a career in business or as a classical flutist. In the end, she decided to go to graduate school for electrical engineering at Stanford University. In 1983, two years before Ochoa completed her Ph.D., Sally Ride, the first American woman in space, made her first shuttle mission.  Ochoa was inspired, in part by Ride, to apply for the astronaut program.  She was accepted and became an astronaut 1991.  She would soon become the first Latina to go to space.

Since then, Ochoa has logged 978 hours in space, earned three patents, and held a slew of leadership posts at NASA that include assignments on four space missions (at least one of which involved a flute recital in space).  Ochoa now serves as Deputy Director of the Johnson Space Center and has received many awards for her work as an engineer, physicist, astronaut, and leader.  She has also traveled around the country sharing her experiences with students in the hopes that they will be inspired to dream big and follow their passions.

For more, visit Latina Women of NASA, the Lemelson-MIT Inventor Archive, and NASA News


Dr. Mario Molina (1943 - )
"I am heartened and humbled that I was able to do something that not only contributed to our understanding of atmospheric chemistry, but also had a profound impact on the global environment."

By age 11, Mario Molina had already decided that he wanted to be a research chemist.  Born in Mexico City in 1943, Molina was hooked on science the first time he peered through a microscope and saw tiny amoebas swimming around. He converted a little-used bathroom in his family's home to a chemistry lab, and, with the help of an aunt who was a chemist, began conducting chemistry experiments appropriate for college freshmen. After attending boarding school in Germany, Molina returned to Mexico to study chemical engineering at Universidad Nacional Autónoma de México (UNAM).  When he graduated, Molina knew he wanted to pursue a Ph.D. in physical chemistry, but he also knew his math and physics skills would be behind other students who had majored in physical chemistry.  He did some graduate coursework in Germany, spent several months studying math on his own, and taught at UNAM before eventually applying to get his doctorate at University of California at Berkeley.

With his Ph.D. in hand, Molina went to work in the lab of F. Sherwood Rowland at the University of California at Irvine. There, he began studying what happens to a class of nonreactive chemicals called chlorofluorocarbons, or CFC's, when they are released into the air.  Molina and Rowland quickly realized that when the sun breaks down CFC's in the upper atmosphere, the chlorine atoms released catalyze a reaction that destroys ozone molecules. That reaction, repeated over and over again, would eventually deplete and lead to thin spots in the Earth's protective layer of ozone.  This realization, combined with work by another scientist named Paul J. Crutzen who was studying the ozone layer over Antarctica, eventually led to a global ban on CFC's--and to the 1995 Nobel Prize in Chemistry for the three researchers.

For more, visit the Nobel Prize Foundation


These are just a handful of the many, many inspiring stories out there, and it was extremely difficult to pick five.  Please share your thoughts with us: which Hispanic scientist(s) do you find most inspiring?


LEARN MORE
If you are interested in learning more about these and other Hispanic leaders in science, check out these resources.

Society for the Advancement of Chicanos and Native Americans in Science

SACNAS Biography Project

The Society of Mexican American Engineers and Scientists (MAES)

SHPE Foundation (Advancing Hispanic Excellence in Technology, Engineering, Math, and Science)

Latinos in Science, Math, and Professions by David E. Newton (book)

Monday, October 1, 2012

Vote! Help Us Rename One of Our Module Collections

We want your input!  Help us rename our collection of modules that includes profiles of scientists at work and case studies of intriguing experiments and discoveries. They include modules like "Studying Climate Change with Kevin Arrigo" and "From Stable Chromosomes to Jumping Genes with Barbara McClintock."

Which name do you like best?


Got another suggestion?  Share it in the comments below.  Thanks!

Thursday, September 27, 2012

Video of the Week: A Tribute to Rachel Carson and Silent Spring


"Over increasingly large areas of the United States spring now comes unheralded by the return of birds, and the early mornings are strangely silent where once they were filled with the beauty of bird song." 
-- Rachel Carson, Silent Spring 1962 


Fifty years ago this week, Rachel Carson's now-famous book Silent Spring rolled off of the presses. It drew widespread attention to the effects of pesticides like DDT on wildlife and human communities and is often credited with launching the modern environmental movement in the United States. The title laments the loss of songbirds to unintentional poisoning.



As a child growing up on a farm in Western Pennsylvania, Carson learned to love and respect birds and other wildlife. Our video of the week is a tribute to Carson and her enormous impact on public understanding of ecology and environmental toxicology in the United States. The Eastern Towhee shown here is one of many birds Carson likely heard singing on her farm during her formative years.  Thanks in large part to Carson's eye-opening book, broad applications of pesticides have been reduced, and there's hope that we will never experience a truly silent spring.

LEARN MORE
Read a brief biography of Rachel Carson and excerpts from her often lyrical writings

Learn more about the Eastern Towhee (including listening to other audio clips of their songs and calls) as well as many other bird species on the Cornell Lab of Ornithology's All About Birds site

Read the first chapter of Lind Lear's Rachel Carson: Witness for Nature, a detailed biography of Carson's life


Have you read Silent Spring or other writings by Rachel Carson? What did you think?

Friday, September 21, 2012

Tragedies in Science: The Crash of the Mars Climate Orbiter

In science, as in the rest of life, things don't always go as planned. From time to time, accidents, mistakes, and tragedies happen. In the worst cases, these experiences result in serious losses or even catastrophes that can affect many people. In less severe cases they are the painful (and sometimes expensive) blunders that we can eventually look back and laugh about.

But in almost every case--whether caused by bad luck, bad planning, lack of understanding, simple human error, or systemic problems in a research team or a society--there is something to be learned from these experiences. Always double check your unit conversions. Train your field crew for the harshest possible conditions and the worst case scenario. Recognize your colleagues and their contributions before it's too late.

The tragedies of science often don't appear in text books or journal articles, but they are just as much a part of science as any discovery or triumph. And, as you'll see in the first installment of our new Tragedies in Science blog series, even "rocket scientists" make mistakes. By taking a closer look at some of the accidents and tragedies of the past, we can find both practical lessons for the future and inspiration for how to persevere and learn from tragedy.


The Crash of the Mars Climate Orbiter 

An artist's concept showing NASA's Mars Climate Orbiter, which was
lost due to a unit conversion error 13 years ago. Image courtesy: NASA/JPL
September 23, 1999 should have been a day of excitement and celebration for researchers and science enthusiasts everywhere. That was the date--13 years ago this Sunday--that NASA's Mars Climate Orbiter was supposed to claim its spot in orbit around the Red Planet, roughly 180 km above the Martian surface. From that vantage point, the Orbiter would monitor conditions and send information back to Earth as part of the Mars Surveyor Program, which launched a series of missions in the 1990's and 2000's to study one of our closest neighbors in the solar system.

But the $125 million Orbiter was doomed.

As the spacecraft neared its destination, the engineers at NASA's Jet Propulsion Laboratory who were guiding the Orbiter thought everything was on target. Then, when the craft made it's final maneuvers to enter orbit, they lost communications. Something was wrong.

By examining data from the previous eight hours of the Orbiter's journey, NASA realized that the craft's approach had been much lower than intended--about 60 km above the planet's surface instead of 150 to 180 km. The altered course meant a rough ride through the Martian atmosphere that the Orbiter was not designed to withstand. The following day, the engineers concluded that the spacecraft had not survived the miscalculation, and the search for the Orbiter was abandoned.

Within a week of the accident, two committees (one internal and one composed of outside experts) had been formed to investigate what had gone wrong. They concluded that a simple mathematical and communications error was at the heart of the problem: one part of the mission team had used English units while the another part of the team had used metric units when making calculations related to the jet thrusters used to correct the Orbiter's trajectory during it's journey. A flubbed unit conversion had cost them a $125 million spacecraft, years of work, and untold scientific knowledge.

Luckily, unit conversion errors are an easy problem to fix, and you can bet NASA won't be repeating that mistake. In a statement released shortly after the crash, Dr. Edward Weiler, NASA's Associate Administrator for Space Science, said: "The problem here was not the error, it was the failure of NASA's systems engineering, and the checks and balances in our processes to detect the error. That's why we lost the spacecraft."
 

LEARN MORE 
Check out our Unit Conversion module for more about the Orbiter's demise and a primer on how to avoid a mistake like NASA's.

See Time's picks for the "Top 10 NASA Flubs."
 
And please let us know what you think of the first installment and the series as a whole! We are also always on the lookout for other tragic stories in science, so please share your ideas.

Friday, September 14, 2012

Image of the Week: Printing Blood Vessels and a Whole Lot More

Blood Vessels Created by 3D Printing
In a paper published this week in the journal Advanced Materials, Dr. Shaochen Chen
demonstrated that blood vessels, which could eventually be used in artificial tissue, can be
created using a new 3D printing technique called dynamic optical projection stereolithography.   
Image courtesy: Biomedical Nanotechnology Laboratory, Chen Research Group, UC San Diego Jacobs School of Engineering

Do you have a good printer at home?  What about one that can print you a new car part, a toy, or another 3D object?  It may sound bizarre, but 3D printing (also known as additive manufacturing because a printer typically builds an object by slowly adding layers of material) is becoming more common in a wide range of contexts, including the battlefield and the medical field.

Our image of the week shows artificial blood vessels printed by researchers in the Biomeidcal Nanoengineering Lab at US San Diego.  Their technique uses light to trigger the formation of a solid 3D structure from a solution containing cells and biomolecules that are photo-sensitive (or reactive to light).  By carefully controlling the beam of light with a series of mirrors, they are able to fabricate tiny, intricate structures like those found in nature.  They believe the new process will lead to better tools for growing cells in the lab and could eventually even allow medical professionals to print tissues for regenerative medicine.

LEARN MORE
Watch an amazing video and read about another application of 3D printing that was recently in the news: a bald eagle named Beauty was given a prosthetic beak made on a 3D printer after being injured by a gunshot. (Warning: although there's a happy ending, images may not be suitable for sensitive readers and viewers.)

Read the Science Insider piece about the newly created National Additive Manufacturing Innovation Institute and the wide potential uses for and benefits of 3D printing.

Read yesterday's story in Reuters about how the business of 3D printing is starting to make its way into individual homes and garages.


Monday, September 10, 2012

The Scientific Method in Action: Advances in Weather Forecasting

Through repeated applications of the scientific method and advances
in computer modeling, weather predication has become a 
scientific endeavor and accuracy has greatly improved.   
Image courtesy: Chris Zielecki (Flickr CC)
Meteorologists often take a lot of flack when their weather predictions aren't accurate--indeed it can be very annoying to cancel a big event for a blizzard that never materializes, or worse, very dangerous if an unexpected storm comes up while you are out hiking. Despite its foibles, though, weather forecasting has come a long way from its early roots of divining celestial signs and following limericks ("red sky at night, sailors delight; red sky in morning, sailors take warning") to become a truly scientific endeavor.

As in any scientific field, uncertainty is inherent in the data that predict the path of a hurricane or separate "clear skies" from "chance of thunderstorms."  But the accuracy of weather forecasts has greatly improved over the last century,  thanks in large part to advances in computer modeling.

Early efforts to predict the weather mathematically, by people like Vilhelm Bjerknes and Lewis Fry Richardson, highlighted the need for serious computational power to begin even approaching the level of complexity found in Earth's atmosphere.  Efforts to make weather prediction scientific, and the recognition that propagating a tiny error across a series of weather calculations could have a huge cumulative impact on the results, also spawned the field of chaos theory.  Chaos theory, which includes the popular notion of "the butterfly effect," aims to understand underlying patterns of behavior in complex systems (like weather) and to quantifying the uncertainty.

Strides in the accuracy of weather prediction are an everyday example of the scientific method in action. Modern meteorologists--as well as scientists who model long-term global climate systems--still contend with uncertainty, complexity, the limits of technology, and human errors.  But through the iterative process of the scientific method (and aided by faster, more powerful computers), they are continuously fine-tuning their models and predictions.  That's good news for science and for anyone who wants to plan a picnic or avoid a lightening strike.

LEARN MORE
Venture inside one of the modern nerve centers for weather forecasting, the National Centers for Environmental Prediction, in Nate Silver's New York Times Magazine piece "The Weatherman is Not a Moron."

Learn about some of the first computer models, which were developed for weather prediction in our module Research Methods: Modeling

Read about how weather forecasting led to the rise of chaos theory in our module Data: Uncertainty, Error, and Confidence

Friday, September 7, 2012

Video of the Week: NASA's Perpetual Ocean Proves Data can be Art

Video courtesy: NASA/Goddard Space Flight Center

Who says data have to come in a dry table? The scientists and animators at NASA's Scientific Visualization Studio (SVS) have made a career out of doing just the opposite. Using some of the same software tools employed by Pixar, they create images and animations that bring data sets to life and make them easier to understand--for both the public and the scientific community. Our video of the week, Perpetual Ocean, is one artful example of their work that recently became popular on social media. By synthesizing a numerical model and a slew of different types of data collected between 2005 and 2007, the SVS team has created a beautiful visualization of the "swirling flows of tens of thousands of ocean currents."

Enjoy.  Happy Friday.


LEARN MORE
Read a Q&A with Dr. Horace Mitchell, Director of NASA Scientific Visualization Studio from Mashable

Learn how the process of visualizing data can help scientists interpret it more easily in our module Data: Using Graphs and Visual Data

Wednesday, September 5, 2012

Unmanned Aircraft Gathers Magnetic Data to Map Underground Faults

SIERRA, or the Sensor Integrated Environmental Remote Research
Aircraft, waits at the airport for her first flight of the season in
Surprise Valley, California. Image courtesy: Melissa Pandika.
Meet SIERRA, or the Sensor Integrated Environmental Remote Research Aircraft, if you want to be formal about it.  She's an independent little aircraft that flies without a pilot, collecting magnetic data to map underground faults and other geophysical features beneath the surface.

Starting this week, a team of scientists and engineers will be working with SIERRA in Surprise Valley, California. The team includes Visionlearning's own Anne Egger, assistant professor of geological sciences and science education at Central Washington University, as well as researchers from the USGS and NASA. The data they gather in Surprise Valley will help them create a three-dimensional map showing the locations of various faults and fissures, revealing how the water that boils up in local hot springs circulates underground, and offering clues about potential earthquake hazards in the area.

Melissa Pandika, a science journalism masters student at Stanford University, is chronicling the field expedition.  You can follow along on the USGS, NASA, or Scientific American Expeditions blogs or on Twitter.  Or browse photos from the field on Flickr.


LEARN MORE
For more about what lies beneath our planet's surface, check out our module Earth Structure: A Virtual Journey to the Center of the Earth



Friday, August 31, 2012

Image of the Week: Six New Species of Millipedes Found in Musuem Collections

A male specimen of Nephopyrgodesmus eungella--one of six new
species of millipede found in leaf litter that was sitting on the shelves
of two Australian museums. Image Courtesy: Robert Mesibov (CC)

Think you have to organize an expedition to an isolated patch of wilderness or the deepest depths of the sea to find news species?  Not hardly.  This week, scientists described six new species and three new genera of millipedes that were found on the shelves of two Australian museums.  Dr. Robert Mesibov, a millipede specialist at the Queen Victoria Museum and Art Gallery, discovered the specimens among the "residue" (in this case bags full of leaf litter) from previous collecting expeditions focused mainly on beetles.  Our image of week shows one of the new species.  All six are described--and shown in beautifully creepy photographic detail--in the open access journal ZooKeys.

LEARN MORE
Find out how scientists classify and name the diversity of life on Earth, in our modules: Taxonomy I and Taxonomy II: Nomenclature.

Read about two new bat species discovered in 2009 among the Smithsonian Institution's mammal collections and a new dinosaur discovered in 2011 in Natural History Museum of London's collections.

See the new species of lacewing scientists in California recently found by browsing photos on Flickr.

Friday, August 24, 2012

Video of the Week: Critical Thinking on Climate Change



Our video of the week is a bit longer than usual: it's a full-length lecture by Dr. Richard Milne from the University of Edinburgh entitled "Critical Thinking on Climate Change: Separating Skepticism from Denial."  Dr. Milne offers a clear and compelling explanation of the difference between true skeptics (who help move science forward by asking tough, legitimate questions) and deniers (who cherry-pick data, rely on false experts, and use other questionable techniques to advance a viewpoint in the face of scientific evidence).

Learn More
For more discussion about what constitutes true scientific controversies and how they are resolved (or not), read our module Ideas in Science: Scientific Controversy.

For more about how visuals, such as graphs, are used and misused, check out our module Data: Using Graphs and Visual Data.

You might also be interested in other lectures in the University of Edinburgh's series "Our Changing World."

And, as always, we love getting your comments. Please let us know what you think! 

Wednesday, August 22, 2012

War Paint Gets a Chemistry Make Over

Soldiers Apply Camouflage Make Up
North Dakota National Guard recruits practice applying camouflage
face paint as part of their training. Chemists from the University of
Southern Mississippi are formulating a new silicon-based paint that
can reflect the intense heat of a bomb blast or fire.
Image: Senior Master Sgt. David Lipp, courtesy of The U.S. National Guard (CC)
This week, thousands of scientists are gathered in Philadelphia, PA for the American Chemical Society's annual meeting.  They'll be doling out the 2012 Heroes of Chemistry awards and discussing all kinds of chemistry-related topics from climate change to drug treatments for chronic diseases

But one symposium in particular caught our eye: Polymers for Personal Care and Cosmetics.  Most of the presentation abstracts focus on the ingredients and chemical properties of familiar products like toothpaste, hairspray, and skin cleansers--which are fascinating in themselves.  But one presentation describes a newly developed camouflage face paint that can shield the skin from the heat of a bomb blast or fire.

For Dr. Robert Lochhead and his research team at the University of Southern Mississippi, developing the prototype of this super make-up for the U.S. Department of Defense was truly a chemistry puzzle. They needed to create face paint that would reflect intense heat but was also waterproof, easy to apply and remove, worked as camouflage, didn't irritate the eyes, and contained at least 35 percent of the insect repellent DEET.

Most commonly used combat face paints have an oil or wax base, which is flammable and may make burns worse by melting to the skin. Lochhead and his team took a cue from many modern cosmetics and substituted silicon for these traditional hydrocarbon ingredients.  Then they used a hydrogel (a network of polymers capable of holding a large amount of water) to encapsulate the DEET and prevent it from catching fire.

In lab tests, the new paint protects skin from intense heat for between 15 and 60 seconds--potentially enough time to allow a soldier or fire fighter to move to safety. The researchers also plan to test it on clothing, tents, and other surfaces that could benefit from extreme heat protection.


LEARN MORE
For more about the purpose and importance of scientific meetings see our module on Scientific Communication: The How and Why of Scientific Meetings.

For more about how professional societies like the ACS help foster scientific progress, read our module on Scientific Institutions and Societies.

For a fun look at the chemistry of everyday items, check out Chemical and Engineering News' "What's that STUFF?" page.

Thursday, August 16, 2012

Image of the Week: The Science of Garbage (Infographic)

Part of the infographic "World of Waste" from Science
Different countries produce different types of waste. An inforgraphic included in the August 10th
edition of the journal Science compares data about waste from around the world.  G. Grullón/Science

When we think of garbage, we tend to think of municipal waste--the trash (and recycling) that comes out of our homes and businesses.  But there's a whole lot more to the waste stream than just what we set out on the curb.  The August 10th special issue of the journal Science, "Working with Waste," looks at both municipal waste and aspects of waste stream we tend not to think about, like leftovers from agriculture, manufacturing, mining, and sanitary (sewage) systems.

Our image of the week gives a tiny taste of one of the many resources included in the special section: a four-page infographic that visualizes and compares data about garbage from around the world.  This image shows a comparison of the types of municipal solid waste thrown away in France and the United States from 1980 to 2005. View the full infographic, or download a pdf.

While some of the scientific papers in the section require a subscription, many of the other resources (like the infographic) are available free for the next month:
  • Listen to the "trashcast" covering Grabology 101; the challenges of recycling rare and precious metals from consumer products; and getting over "the yuck factor," a purely psychological barrier to handing human waste efficiently
  •  
  • Watch a video about efforts to invent a "Toilet 2.0" that more efficiently deals with human waste

For more about visualizing scientific data, see our module "Data: Using Graphs and Visual Data."


Friday, August 10, 2012

Image of the Week: New Fossil Skull Fragments Suggest Greater Complexity in Humanity's Family Tree

The cranium known as 1470, which was discovered in 1972, is shown
pieced together with a lower jaw discovered in Kenya in 2009 and
believed to belong to the same early Homo species.
© Photo by Fred Spoor

In 1972, archaeologists working in Kenya unearthed a mystery: a partial skull with a long, flat face and a large cranium. For the first half of the 20th Century, scientists thought the evolutionary tree for modern humans (Homo sapiens) was pretty simple. We had evolved from Homo erectus on a fairly straight and branchless path, with evidence of only one other Homo species (dubbed Homo habilis) that predated and overlapped with Homo erectus. But the skull, known as 1470, suggested that there might have been another Homo species--a distant cousin of modern humans--living in Africa alongside our direct ancestor Homo erectus about 2 million years ago. With only one specimen to go on, scientists disagreed about whether 1470 truly represented a separate species or simply showed the range of variation in the previously known Homo species.

This week, scientists announced that they had found portions of three additional skulls, which appear to confirm that 1470 was not a complete anomaly and suggest that there were two additional Homo species living alongside Homo erectus. Our image of the week shows one of the new fossils, a lower jaw bone, fit together with 1470 (with the help of computer imaging).

Even with the new evidence, the debate continues about how many distinct Homo species were living in Africa between one and two million years ago. What is certain is that scientists have a new reason to closely examine the shape and complexity of our family tree.

Learn More
Read more about the discovery in the New York Times, Science News, or the press release from the Turkana Basin Institute and National Geographic.

Thursday, August 2, 2012

Image of the Week: NASA's Curiosity to Land on Mars Sunday

An artist's rendering of Curiosity in the Gale Crater on Mars. Image Courtesy: NASA/JPL-Caltech

You can bet that scientists at NASA's Jet Propulsion Laboratory will be at work late this Sunday.  In fact, they'll likely be at the edge of their seats until at least 10:31 pm local (Pacific) time--that's when the new Mars rover Curiosity is scheduled to touch down and begin its search for evidence of life on  the Red Planet. Just landing the car-sized rover safely in Mars' Gale Crater will be a feat of physics. (Among other things, it requires a maneuver engineers call a sky crane, which involves lowering the rover on a cable from a hovering rocket stage released by a passing spacecraft.)

Once Curiosity has its wheels under it, it will be a rolling geology and chemistry lab. It's equipped with cameras, a drill, a sieve, analytical tools for assessing the chemical composition of air and soil samples, and laser called the "ChemCam" that can vaporize bits of rock from roughly nine meters (30 feet) away and test their composition. Our image of the week shows an artist's rendering of the Curiosity examining Martian rocks with a set of tools at the end of its two-meter (seven-foot) arm.


LEARN MORE
Visit NASA's "Follow Your Curiosity" page to see more images, watch a video simulation of the Curiosity's landing, download fact sheets about the rover, or find a landing party in your state.

TELL US
Will you be watching?  If you're an educator, are you using the landing as a teaching opportunity?

Wednesday, July 25, 2012

Video of the Week: Science of the Olympics

In addition to being an outstanding athlete, Olympic
weightlifter Sarah Robles is a model for scientists
working in biomimitics. Image courtesy: NBC Universal 
Only two days, 1 hour, and 1 minute to go until the 2012 Summer Olympic Games kick off in London. We tend to think of the Olympics as a contest of strength, endurance, and human will--and indeed it is. But there's another, less-talked-about aspect of the games that has major implications for athletes in training and competition: science.  From designing "anti-gravity" training treadmills and high-impact safety helmets to making fluid dynamics work for an athlete in the pool, science and engineering are at work behind the scenes in all of our favorite Olympic sports.

Our video of the week looks at how scientists studying biomimitics (the practice of using nature as a model to solve engineering problems) can apply techniques used by champion weightlifter Sarah Robles to the development of robotic arms.  It's one of ten videos in the new series "Science of the Olympic Games: Engineering in Sports" produced by the National Science Foundation and NBC Learn. The other nine videos cover topics ranging from the biomechanics of Jamaican sprinter Usain Bolt's impressive speed to the importance of accuracy and precision in timekeeping.

 

Congratulations and best of luck to all the athletes competing in London this summer!

Thursday, July 19, 2012

Video of the Week: E.O. Wilson's Advice to Young Scientists about Facing Math and Excelling in Your Field

For many students, even those majoring in science, math is a four-letter word. But renowned evolutionary biologist E.O. Wilson has a message for aspiring scientists:  "If you are a bit short in mathematical skills, don't worry."

Wilson--who didn't take algebra until his freshman year of college or calculus until he was 32 and a tenured professor at Harvard--wants students and young scientists to know that they can catch up. 
In our video of the week, Wilson offers advice on how to tackle fear of math, how to find the field of study that fits you, and how to excel even if math isn't your strong suit. He implores young people to go into the sciences, saying: "The world needs you, badly."



At Visionlearning, we know that many students struggle with the mathematical components of their science courses.  That's why we're excited to begin work on a series of new modules covering mathematical concepts and skills commonly used in the sciences, from biology to geology. We'll let you know when the first module is ready, and we hope you'll give us your feedback. 

In the meantime, is there a mathematical concept that you (or your students) struggle with?  Has there ever been a time when math held you back in your career or studies?

Thursday, July 12, 2012

Video of the Week: EU's 'Science, It's a Girl Thing' Stirs Controversy

This week the European Union launched a new initiative called "Science: It's a Girl Thing" aimed at encouraging more young women to pursue STEM careers.  Their promotional video clip drew a lot of attention--although not the kind they had hoped. In fact, they were so besieged with complaints that the video was superficial and filled with stereotypes that they withdrew it and issued an explanation and apology.  The clip, still available through YouTube, is our Video of the Week.

We hope you'll watch it and share your opinion in the comments below or on our Facebook page:




What Others are Saying
Mary Ann Rankin, President and CEO of the U.S. National Math and Science Initiative, calls the video "a viral disaster" but notes that many of the other materials for the initiative are "quite good."  In particular, she points to a series of video profiles featuring female scientists produced by the campaign and a section called "Six Reasons Science Needs You," which makes the case for women to get excited about STEM opportunities.

In a statement, the European Union explained the rationale behind the video clip and said it will continue the "Science: It's a Girl Thing" campaign sans music video:
The 45-second clip was intended to put this in a lighter context, to grab the attention of teenage girls aged 13 to 18 who have up until now been very hard to reach with messages about science. The goal was to attract their attention so that they might look at the campaign in detail, visit the website where there is lots of information on science and careers in research, including video-profiles of role models.

The concept of the trailer was to combine images of science (such as electronics, mathematics, chemistry, physics) with images closer to cosmetics and fashion to show teenage girls that science is already part of their life.


What do you think?  Is the video effective?  Offensive?

Wednesday, July 11, 2012

Controversy over Arsenic-Loving Bacteria comes down to Data Interpretation

Mono Lake, California, home to the controversial, arsenic-tolerant
bacteria known as GFAJ-1.  Image Courtesy Flickr User anaurath (CC)

A little over a year ago, we ran a blog post about a provocative paper in the journal Science called "A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus." Or more accurately, we ran a blog post about the heated discussion and, yes, controversy surrounding the paper.

The researchers' findings were startling because they pointed to a life form--a bacterium called GFAJ-1--that, according to the authors' interpretation of the data, did not need phosphorus to survive. In fact, the authors, led by NASA astrobiology fellow Felisa Wolfe-Simon, posited that the bacteria were replacing the phosphorus in their DNA with the normally-toxic metal arsenic.

The implications were huge. If the results were reproduced by other researchers, our understanding of what makes life possible, on Earth and potentially on other planets, would need serious revision. As soon as the paper appeared online, debate raged in the scientific community. When the paper went to press a couple of months later, it was published alongside eight "technical comments" voicing concerns about the paper's conclusions as well as a rebuttal from the researchers.

Fast forward to this Monday--July 8, 2012.

Two new papers on GFAJ-1 have been published in the online version of Science, both of which suggest that the conclusions drawn in the original study were wrong. The second round of researchers--led by Tobias Erb at the Institute of Microbiology, ETH in Zurich and Marshall Louis Reaves at Princeton--took a closer look at the situation.  They grew the same bacteria (provided by the original authors) in arsenic-rich and phosphorus-depleted conditions. For the most part, their results were similar to the original study--the bacteria did indeed continue to grow in these adverse conditions, and they did find arsenic in its cells.

But when they examined the bacteria's DNA and cellular byproducts more closely, they came to different conclusions than Wolfe-Simon's team had. The new results and their revised interpretation of the data indicate that GFAJ-1 bacteria is very resistant to arsenic (a feat in and of itself), but that it does not incorporate the metal into its genetic material and that it still needs a small amount of phosphorus to survive.

So what happened?  Was the first study "bad science?"  Did the system of peer review fail?  Does this mean that we've wasted our time studying and reading about GFAJ-1?

On the contrary.  This is the process of science. This is how our understanding of the natural world grows and evolves.

In a press statement released with the new papers, the editors of Science summed it up this way:
The scientific process is a naturally self-correcting one, as scientists attempt to replicate published results. Science is pleased to publish additional information on GFAJ-1, an extraordinarily resistant organism that should be of interest for further study, particularly related to arsenic-tolerance mechanisms.

THEN AND NOW:

Compare the Headlines:
New York Times Story "Microbe Finds Arsenic Tasty; Redefines Life," Dec. 2, 2010

New York Times Story "Studies Rebut Finding That Arsenic May Support Life" July 8, 2012


Compare the Papers:
The Original Science Paper, "A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus" Dec. 2, 2010

The Technical Comments and Rebuttal from the authors, May 27th 2011


The New Science Papers, July 8, 2012
"GFAJ-1 Is an Arsenate-Resistant, Phosphate-Dependent Organism"

"Absence of Detectable Arsenate in DNA from Arsenate-Grown GFAJ-1 Cells"

Note: All related papers are free to access, but you may need to register with AAAS.

Thursday, July 5, 2012

Image of the Week: Has the Elusive Higgs Boson been Found?


Unless you were hiding under a rock this week, you likely heard the buzz about the Higgs boson (or perhaps more accurately the "Higgs-like particle"). The sub-atomic particle, proposed in 1964 by Peter Higgs and other theorists, has eluded scientist for decades. But on Wednesday July 4th, scientists announced that they had amassed enough evidence to officially describe a new sub-atomic particle--one with characteristics closely matched to the long-sought-after Higgs boson.

Image © 2012 CERN
For two years, physicists working at the Large Hadron Collider (LHC) near Geneva, Switzerland have been smashing protons together at high speeds and observing the crash sites with sensitive detectors. They were looking for signs that the collisions had (at least occasionally) emitted a Higgs boson, which according to its theoretical properties would immediately decay into other particles. Our image of the week is a computer rendering of one of the experimental collisions. The yellow dotted lines and green towers radiating out from the crash show characteristics matching what scientists would expect to observe as a Higgs boson decayed into a pair of photons.

By examining the subatomic shrapnel from trillions of collisions, the scientists were able to conclude that they had indeed shaken loose this new Higgs-like particle.  This is big news because the Higgs boson is the last piece "missing" (undetected by science) from the "Standard Model" of particle physics that describes the structure of matter and our universe.

While the researchers are cautious about saying that the particle they have observed is definitely the Higgs boson, they are certain that it's a huge discovery for physics. And the possibility that it's a different, as-yet-unpredicted particle is equally as exciting. To gain a clearer picture of the discovery, the research teams will gather as much data as possible before the LHC shuts down for a two-year period of maintenance and upgrades.


Bonus footage! We selected an image of the week, but we couldn't resist sharing this video as well. NOVA produced it last year when scientists were still searching for evidence of the Higgs boson. It's a little dated in that respect, but it gives a nice, quick explanation of the Higgs boson and an interview with Peter Higgs.

Watch The Higgs Particle Matters on PBS. See more from NOVA.

Dig Deeper
Learn more about the LCH, the massive (27-kilometer-long) particle accelerator, where scientists labored to find evidence of the Higgs boson

Read the Science News story "Higgs Found" by Alexandra Witze



Friday, June 29, 2012

Earthquake Module that Engages Students with Real-Time Data Receives Award

Dr. Anne Egger teaching students in the field.
Image Courtesy: Nick Zentner, Central Washington University
We're proud to announce that Visionlearning's own Dr. Anne Egger has been awarded the prestigious Science Prize for Inquiry-Based Instruction for her learning module "Seismicity and Relative Risk."

Dr. Egger, assistant professor of geological sciences and science education at Central Washington University, developed the module over nine years of teaching introductory geoscience courses and trying different approaches to engage students in both the topic of earthquakes and process of analyzing data. "The challenge in an intro class is helping students engage when they've often already decided they're going to do something else," she says.

After several iterations, Egger created the current version of the module, which makes use of real-time earthquake data collected by the U.S. Geological Survey (USGS). By having her students complete a series of activities interspersed with discussion, Egger has been able to turn "dots on a map" (the data points representing earthquakes around the world) into something meaningful to the students. In the final stage of the module, Egger's students write essays comparing the seismic activity and relative risk in three cities where they would consider living after graduation. Not only do the students get excited during the discussion, but Egger has found that their assignments are much more interesting to read and less repetitive than past assignments.

Perhaps best of all, the module is free and can be used anywhere in the world. "This module is utterly adaptable to wherever you are, with whatever students, using a computer, or a smart phone—you name it. There are earthquakes to look at all around the world," Egger says.

Learn more:
Read Dr. Egger's essay about the module and the process of using real-time data in the classroom, which appears in today's edition of the journal Science. Then try out the module in your classroom or at home--from any computer or smart phone. It includes a downloadable student activity sheet, PowerPoint presentation for lecture, and writing assignment with a grading rubric.

For more about the history of plate tectonics and the forces that cause earthquakes, check out modules Plate Tectonics I: The Evidence for a Geologic Revolution and Plate Tectonics II: Plates, Plate Boundaries, and Driving Forces.

Explore real-time data collected by seismometers all over the world by visiting the USGS Earthquake Hazards Program website

Find out more about the Science Prize for Inquiry-Based Instruction

Monday, June 18, 2012

Darwin Tunes: Scientists Examine How Consumer Choice Can Drive the Evolution of Music from Noise

Image Courtesy: Flickr User all that improbable blue (CC)
Here's an application of evolutionary theory you don't see everyday: the evolution of music by natural, make that public selection.

Researchers from the Department of Life Sciences at the Imperial College of London and the Media Interaction Group at the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan joined forces to investigate how consumer preferences--as opposed to directed artistic efforts--can affect the evolution of music.  They set out to answer some very interesting questions, including:  Is it possible to make music without a composer? If so, what kind of music is made? What limits the evolution of music?

Inspired by research on evolution in microbes and studies on how art and music develop and change in response to cultural forces, the team created "Darwin Tunes," a computer-based system for simulating natural selection within a "population" of audio clips. Darwin Tunes is powered by an algorithm that creates "digital genomes"--computer programs, which, when executed, create short loops of sound. Like a biological genome that serves as a blueprint for an organism, each digital genome specifies certain parameters--in this case things like instrumentation and note placement. The algorithm does not receive any melodies, rhythms, or other human-created sounds as inputs, so the music created by Darwin Tunes is truly computer-generated.

Running the algorithm once produces a population of 100 audio loops that go through a number of "life cycles" during the course of the experiment. Which loops get to "reproduce" and which "die off" is determined by the ratings given by a group of nearly 7,000 human listeners who use a five-point scale ranging from "I can't stand it" to "I love it." Those clips that are deemed most pleasing reproduce and those that are hard-on-the-ears go extinct. In evolutionary terms, listener ratings are the "selective pressure" acting on the population.

As with living organisms, the offspring of the audio loops differ from their parents for reasons that also mirror biological evolution.  Each audio loop in the second generation is produced by combining the genomes of two first-generation loops (akin to sexual reproduction in nature). The genomes of the second generation are also modified with new, random musical "genetic material" akin to DNA mutations in nature. Each new generation is again rated by listeners.

By repeating this process a few thousand times, the research team found that clips changed over time--moving from sound that would most aptly be called "noise" to sound that qualified as "music." The difference is easy to hear in the clips below, which contain loops produced initially by Darwin Tunes (generation zero), loops from generation 1,500, and loops from generation 3,000.


Generation Zero

Generation 1500

Generation 3000

As any musician or music lover can tell you, the qualities that make a piece of music appealing are complex. To better understand which traits were being "selected for" in the Darwin Tunes populations, the researchers looked to the emerging field of music information retrieval (MIR) technology. MIR is what allows services like Pandora and iTunes to suggest new music based on the songs already on a user's playlist. Using two MIR algorithms to analyze the various generations of clips (both those that evolved with listener input and controls that were randomly assigned ratings), the researchers identified two specific traits that were changing over time: the presence of chords commonly used in popular music and the complexity of rhythmic patterns in the music.

While these two features are clearly important, the researchers conclude that there are many other musical factors in the evolution of these clips and that additional experiments using a wider variety of MRI algorithms would be interesting. The results of the study appear in today's early online edition of the Proceedings of the National Academy of Sciences. You can listen to and rate clips by visiting the Darwin Tunes website.

For more about evolution and natural selection, browse our modules on Adaptation and Charles Darwin (and don't miss Part 2 or Part 3!).


Want to read more about the science of music? Check out the research conducted by the Pattern Analysis and Intelligent Systems Research Group at the University of Bristol. Their work to develop a mathematical equation that can predict hit songs was presented in December 2011 at the 4th International Workshop on Machine Learning and Music. Visit their Score a Hit website or download the short paper that appeared in the conference proceedings.