Tag Archives: Physics

Rural Internet Access and Diversity in STEM

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https://commons.wikimedia.org/wiki/File:Left_to_right_Chien-shiung_Wu_(1912-1997)_and_Dr._Brode_(6891734435).jpg

As you can see, white men have typically dominated physics research. Dr. Chien-shiung Wu (1912-1997), professor of physics at Columbia University, with “Dr. Brode”

It is no secret that many STEM fields, especially physics and engineering, suffer from a lack of equal representation by race, ethnicity, and gender. Approximately 75% of all physics degrees go to white scientists, and 80% of those degrees to go men. While much of the work in inclusivity in STEM has focused (for good reason) on women and racial/ethnic minorities, there is also an underrepresentation of scientists from rural geographic locations. A common problem contributing to the lack of diversity in science is the lack of diverse role models and representations of scientists in the media. Other factors involve the complex intersection of socioeconomic status and access to resources like textbooks, science equipment, and high-speed internet. Because the internet is both an avenue for information transfer and a platform for seeing diverse role models, the importance of internet access cannot be overemphasized in its impact on fostering inclusivity in STEM. Resting at the crux of the diversity in STEM problem and lack of internet access is rural America. In an effort to make science accessible to geographically diverse populations and thereby attract as many talented students as possible, scientists should advocate for wide-spread, affordable, high-speed internet access for all.

Diversity produces better science

While the diversity buzzword has generated a lot of press recently, many in the science community and beyond still roll their eyes at diversity efforts and question the utility of programs aimed at increasing diversity in STEM merely for diversity’s sake. But, it turns out that including diverse perspectives actually makes you do better science: diversity improves problem solving, makes your papers more likely to be cited, makes you prepare stronger arguments, and prevents groupthink. With so much evidence that diversity is good for science, it is unequivocally in our best interest to foster inclusive environments and make science accessible to as wide a range of people as possible. But, to make science accessible, we must first make internet accessible.

Internet’s Critical Role

Over the past decade, the internet has quickly morphed into an absolute necessity for modern living. Bills are posted and paid online. Retail is moving online. Even brick-and-mortar stores now use internet services to process credit card payments or digitally cash checks. And of course, the internet has become the main avenue for information transfer. Schools post assignments online and online information repositories have replaced physical textbooks in many schools. Science news is largely disseminated via Facebook, Twitter, online radio streaming, online journals, podcasts, and Youtube. Google is an invaluable tool for the student of science at any education level. Scientific journals necessary for professional science are increasingly moving from print to online formats.

https://pixabay.com/en/social-media-3d-render-bubble-2636256/

Social media connects scientists around the world.

In addition to being essential for learning science, the internet is also a crucial tool for finding diverse representations of scientists. Diverse representation of scientists is vital because when it comes to role models, seeing is believing. Growing up without internet access and only local tv programming, the only scientists I could name were Albert Einstein and Bill Nye the Science Guy. With the advent of social media, users now have access to online communities like the National Society of Hispanic Physicists and the #BlackinSTEM community. For students without ready access to online media, their access to scientific role models and science resources will be severely restricted. This may be a contributing factor to the underrepresentation in STEM of students from rural areas where high-speed internet is unavailable.

 

High-speed internet unavailable in many rural areas

In 2016, the Federal Communications Commission (FCC) defined broadband internet as 25 Mbps download speed and 3 Mbps upload speed. According to that same report, roughly 10% of Americans lack access to those speeds. Of the 10% lacking access, 70% live in rural areas. Put in the context of the total population of rural Americans, this means that about one-fourth of all rural Americans lack access to high-speed internet. Further, this report merely addresses the availability of high-speed internet without taking into account the prohibitive costs for many consumers. The true accessibility of high-speed internet depends not only on having the infrastructure in place, but also on imposing regulatory pricing so that high-speed internet is affordable everywhere.

https://commons.wikimedia.org/wiki/File:Ch3e3d.png

Map of the U.S. showing broadband internet access by county

The reason high-speed internet is unavailable in so much of rural America is simply because it is not cost-effective for the internet service providers to install the infrastructure in areas with low population densities. Even in well-established cities, you don’t have to go very far to find that internet availability has suddenly disappeared. At my apartment in Carrboro, I can access up to 400 Mbps internet services. (Again, whether or not anyone could ever afford to pay for 400 Mbps is another story.) Just 12 miles away, outside the city limits of Hillsborough, my father has access to only 3 Mbps speeds no matter how much he is willing to pay. With speeds this slow, video streaming is impossible and even surfing the web quickly becomes frustrating or impossible. Certainly areas which lack high-speed internet access have a significant handicap in the dissemination of science information, resources, and models.

Internet access and geographic diversity in STEM

While there are probably many reasons factoring into the lack of geographic diversity in STEM, one of them is not that students from rural areas are inadequately prepared for STEM classes at the collegiate level. According a 2007 report by the U.S. Department of Education, students in rural areas performed as well as or slightly better on standardized math and science tests as compared to their peers in urban and suburban areas in grades 4, 8, and 12 (pgs 50 and 54 of that report). However, at the college level, rural students are severely underrepresented in STEM fields, and this under-representation may have grown worse in recent years. This implies that science is suffering by not attracting talented students from diverse geographic locations.

One of the barriers preventing rural students from entering STEM fields is the lack of high-speed internet access in rural areas. Because the internet is not being treated as a utility, there is currently no federal mandate that high-speed internet access be made available nationwide. Further, internet is not subject to the same federal ratemaking regulations as are electricity and natural gas to prevent providers from suddenly introducing huge rate hikes. Some companies such as Microsoft have publicized long-term plans to implement the infrastructure needed to make high-speed internet available in rural areas, but progress is difficult to see. Until then, some rural communities have taken matters into their own hands and are building their own community broadband networks. This progress is slow and relies on individual communities having the resources to individually finance their internet infrastructure installation. If we really want to increase access to science and foster diversity in science, scientists should turn some attention to making high-speed internet accessible and affordable for all. 

Peer edited by Jon Meyers and Sara Musetti.

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Space Travel is Possible with the Sound of Light

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https://commons.wikimedia.org/wiki/File%3ASpace_travel_195807.jpg

Optical communication devices may be the first step in space travel.

Technology moguls dream of human colonies on other planets. For this dream to become reality, science needs to develop new spacecraft capable of transporting people and cargo to the outer reaches of our galaxy. Another challenge is how to find a route to these other planets.  We can’t just use Google Maps. Space travelers would have to navigate around comets, space debris, or orbiting planets.  Complex models and communications developments would be needed to move through galaxies safely and quickly.

Light-based communication is desirable because it can transmit more data per second while producing significantly less heat. This means that less energy is spent cooling equipment, making the it more efficient to run compared to conventional electron-based communication.

Similar to how electronic devices maneuver electrons through a computer chip, photonic devices maneuver light for optical communication. Normally, a magnetic field is required to produce a change in optical properties necessary for one-way light propagation. However, the size of magnets are too large to be incorporated efficiently into nanoscale devices. To address this problem, University of Illinois researchers created a nanoscale photonic device called an optical isolator, using sound waves instead of magnets for one-way light guidance.

Erika Van Goethem

Cartoon of optical device

The optical isolator device is made from aluminum nitride. A radio frequency driver (RF driver) generates a radio frequency signal that is used to create a sound wave. The RF signal is applied to an IDT, consisting of two interlocking comb-shaped arrays of metallic electrodes that convert electrical signals into surface sound waves. The grating couplers allow the light, generated by a laser, to enter into the device from one direction.  The light travels along the optical waveguides and is transferred from one optical band to another, interacting with the previously converted sound waves. Light is able to pass through the device when the shape of the light wave matches the shape of the sound wave going in the same direction. However, light waves going in the opposite direction of sound waves are absorbed by the device and are unable to pass through, thus maintaining the one-way propagation of light.

This new device allows for a more reliable and sensitive transfer of information that can be used in devices such as atomic clocks and GPS.  Such innovations may be the first step toward developing deep space navigation and travel.

Peer edited by Portia Flowers.

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Uncovering Ancient Mysteries with Cosmic Rays

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https://en.wikipedia.org/wiki/Giza_pyramid_complex

The Giza pyramids. The center pyramid (tallest) is the pyramid for King Khufu.

You probably don’t usually think of particle physics and the Great Pyramid of Giza as having much in common. In some ways, the two seem diametrically opposed: the Giza Pyramid is the pinnacle of past achievement while particle physics relies on cutting-edge technology. The Great Pyramid of Giza is the only one of the seven wonders of the ancient world that is still standing. It is the tomb built over 4,500 years ago as a monument to Pharaoh Khufu. Little is known about how such a massive structure was built so long ago or what the internal structure looks like. Historians and archaeologists have been trying to uncover these mysteries for centuries. On the other hand, particle physics is often portrayed in movies and TV as a futuristic discipline in which scientists develop futuristic weapons. As a result, when an article was published in Nature on November 2 with the title “Discovery of a big void in Khufu’s Pyramid by observation of cosmic-ray muons,” there was a media frenzy. 

What are cosmic rays?

Though we sometimes think of science as a means to developing a more technological future, it is also importantly a means to understanding the secrets of the past. Much of the information we have about the origins of the universe and the evolution of galaxies has come from studying the fundamental building blocks of matter. For example, some particle physicists study the atomic nuclei falling toward Earth’s surface in cosmic rays. Studying this material provides insight into how galaxies are formed and how they evolved chemically.

When the protons and other nuclei in cosmic rays collide with nuclei in Earth’s atmosphere, pions are created. Pions then quickly decay and form muons. Muons have a negative charge like an electron but 207 times greater mass. The Earth’s atmosphere slows down all of the particles in the cosmic ray showers that are constantly raining down on the Earth. Because of their relatively large mass, muons are actually able to reach the surface of the Earth, unlike lighter particles. Detectors on or near the Earth’s surface can then detect these particles. In order to eliminate background noise from measurements, some particle detectors are placed deep underground in mines and caves. Learn more about what it is like to conduct scientific research in an underground laboratory in Underground Science at SNOLAB.

Using muon detection as an imaging technique

As early as 1955, physicists have taken advantage of the ability of muons to penetrate through rock by measuring the thickness of rock formations using muon flux (the amount of muons passing through an area of a detector). The concept of these measurements is similar to x-ray imaging. An x-ray is a high-energy form of electromagnetic radiation. Due to their high energy, x-rays are not readily absorbed by soft tissue such as skin and organs but are absorbed by denser structures like bone. If an x-ray source is aimed at a human arm and a film is placed on the other side of the arm, an image of the bones will be formed by the relatively low number of x-rays that reach the film behind the bones. Similarly, physicists working with cosmic rays realized that they could image large structures by taking advantage of the the fact that higher-density materials (such as stone) will absorb more muons than areas of lower density (such as air).

 Muon detection is a promising method for studying the pyramids because we can infer information about the internal structure without having to destroy it or to open up sealed sections. In 1970, researchers first attempted to use muon flux to search for cavities in the Giza pyramid. By placing detectors in the subterranean chamber (label 5 in the schematic diagram below), they were able to image a region of the pyramid occupying approximately 19% of the pyramid’s total volume. No new chambers were discovered in this region. Since then, detector technology has become more sensitive to smaller amounts of muon flux. In 2015, a team comprised of researchers from universities in Japan, France, and Egypt tried once again to use muon detection to search for cavities within the great stone structure. They tried three methods of muon detection, and this time they were successful.

 

https://commons.wikimedia.org/wiki/File:Cheops-Pyramid.svg

Cross-sectional schematic diagram of the Great Pyramid of Giza. 1) Original entrance 2) Forced entrance 3) Granite blocks which blocked off passage 4) Descending passage 5) Subterranean chamber 6) Ascending chamber 7) Queen’s chamber. 8) Horizontal passage 9) the Great Gallery, above which the void was detected. 10) King’s chamber & air shafts 11) Antechamber 12) Well shaft

Detection of the new void

First, they placed detectors inside the Queen’s chamber and in the corridor outside. These measurements were taken over the course of several months so that a relatively high number of muons would be recorded, making the measurements more accurate. The measured muon signals were compared with the signals they would expect based on what was previously known about the structure of the pyramid. From this method, they detected an unexpected excess of muons coming from the region above the Great Gallery. From this excess, the researchers inferred that there was an unexpected region of air inside the pyramid. The excess of muons is about the same as the excess of muons that pass through the Great Gallery, meaning the the newly detected void is approximately the same size as the Great Gallery. In order to verify their findings, the researchers used two additional muon-detection methods over the course of the next two years with detectors placed in different locations. Signals from all three methods pointed to the same conclusion: there exists a void in the stone structure above and parallel to the grand gallery.

 

While this information doesn’t directly tell us why or how the pyramid was built the way that it was, it adds to our knowledge about the structure and may help archaeologists infer something about the design. Although, since the publication of the article, there has been some controversy over whether or not this is actually new information, this research still clearly demonstrates that cosmic rays may be useful for understanding not only events that happened billions of years ago but also events that happened much closer to home. And importantly, this shows that science and the humanities have something to offer each other. As scientific advances continue to shape the political and cultural landscape of our future, we will also understand more and more about our past.

Peer edited by Mimi Huang and Jon Meyers.

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Artificial Intelligence: Should We Trust It?

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If you’ve been following the news lately, you’ve probably read about the boom in Artificial Intelligence (AI). Some of the advances have elicited responses ranging from amazement to fear. So why has so much attention been diverted to AI recently? Advances in this technology over the past decade have surprised even experts in the field, and it has been spurred in part by cheaper and faster computing power as well as greater availability of large datasets. AI isn’t some futuristic technology that threatens to change our lives in the distant future, it has already changed our lives in many ways since its inception 60 years ago. Contrary to what many fear, however, it has not yet reached the point of surpassing human capabilities.

Definition and Scope of AI

The portrayal of problematic AI is pervasive in the film industry and can often be misleading. For a technology so widely discussed in popular culture, there’s no consensus on what it actually is. Stanford University’s 100-year study of AI defines it as “activity devoted to making machines intelligent, and intelligence is that quality that enables an entity to function appropriately and with foresight in its environment.” This definition may explain why my calculator isn’t intelligent, but what about my iPhone? It seems the key is that AI achieves specific goals through methods parallel to human intelligence. Most progress in AI today is within specific subfields like machine learning and deep neural networks, which has enabled the next generation of speech-recognition on the Amazon Alexa or the facial-recognition on the new iPhone X. Future uses of AI include autonomous self-driving cars, diagnostic healthcare and several other applications that we don’t yet have the foresight to predict. According to experts, AI doesn’t have the capabilities that match human intelligence but it does have the ability to process massive amounts of data and learn from it in ways humans can’t. With increasingly available big data and cheap computing power, it won’t take long for us to train computers to make extremely accurate weather predictions, find new drug targets, or mine complex biological datasets in a fraction of the time that humans can. AI is being tested on games like Go, Jeopardy and Dota 2 as a low-risk way to improve its algorithm and to demonstrate the human-like abilities of this technology.

Benefits and Drawbacks

https://www.pexels.com/photo/coding-computer-data-depth-of-field-577585/

Artificial Intelligence is exceeding our expectations but are we ready for the changes it brings?

In 2015, Stephen Hawking, Elon Musk and several other scientists and intellectuals signed  an open letter on artificial intelligence, specifically calling for more research on the potential impacts of AI on society. While they discuss several potential benefits of AI, scientists are also wary of the pitfalls and the possibility of losing control of autonomous AI. They believe that the rapid development of AI could threaten to shift society in ways similar to the industrial revolution or the creation of the atomic bomb; inventions that forever changed the social and economic landscape of the world. Another concern is the displacement of humans by robots in many fields. What kinds of jobs will become obsolete? This process of new technology getting rid of certain jobs is nothing new, but it could happen at a higher frequency. Therefore, more research is required to understand how the integration of new AI would affect certain industries.

Should we trust it?

There is no turning back from the future of AI. However, we as a society can engage on how we want to live amidst this increasingly powerful technology. During the past few decades, with the rise of social media, smartphones and cybersecurity issues, technological advancements have already forced us to think about the intersection of humanity and technology. Many scientists and intellectuals warn that AI is more advanced than anything we’ve ever dealt with. Therefore, healthy skepticism is warranted, but not so much that it hinders progress and inspires fear. The US is currently at the forefront of AI research, with China and Russia close behind. The technology is undergoing rapid progress so tighter regulation may slow research down. The existing technological hurdles gives society time to determine what roles we want AI to play in our lives. Some believe that this technology is merely an extension of human values and that our intentions will determine what our future with AI looks like. While this might be slightly naive, I believe that with the proper regulation set in place, we can make a better world more integrated with advanced technology.

Organizations Involved in A.I. Research and Outreach

  • Future of Life: A volunteer-run organization aimed at mitigating the existential risks to humanity from advanced AI.
  • OpenAI: An organization founded by Elon Musk to discover a path towards safe AI
  • Intelligence & Autonomy: A research organization funded by the Ethics and Governance of Artificial Intelligence Fund to “provide nuanced understanding of emerging technologies and to inform the design, evaluation, and regulation of AI-driven systems.”
  • Machine Intelligence Research Institute (MIRI): Aims to make intelligent systems behave in a manner that aligns with human intentions.
  • Future of Humanity Institute (FHI): A multidisciplinary research institute that publishes on AI governance, safety and other issues like biotechnology to shed light on humanity’s long-term future.
  • Stanford’s One Hundred Year Study on Artificial Intelligence (AI100):  To anticipate the effects of AI through a century-long chain of standing committees, study panels and growing digital archive.
  • National Science and Technology Council (NSTC): An executive branch advisory council released two documents highlighting comprehensive research and development plans for AI during the Obama administration (briefs for the Strategic plan and Preparation here). However, since this office has not been staffed under the new administration, it is unclear what steps will be taken by the government.

Peer edited by Gowri Natarajan.

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Physics Through the Looking Glass

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On Christmas Eve 1956, a woman caught the last train to New York in the snow to report experimental results that would alter the landscape of modern physics forever. Although members of the physics community would initially dismiss her results as nonsense, the evidence would soon become incontrovertible, launching many scientific possibilities.

https://commons.wikimedia.org/wiki/File:Chien-shiung_Wu_(1912-1997)_C.jpg

C. S. Wu working in the lab.

The scientist’s name was Chien-Shiung Wu, and it took her many years of study and perseverance to make this discovery. Starting at a young age, she was quite curious about the natural world. Chien-Shiung Wu’s father, Zhongyi Wu, was an engineer who believed strongly in equal rights for women. He started the first school for girls in his region of China. Chien-Shiung Wu was one of the first girls to obtain a formal education in China. She rapidly outpaced her peers, and proceeded to an all-girls boarding school 50 miles from her home. She continued on to college in Nanjing before traveling across the globe to pursue her graduate degree at University of California, Berkeley, in the US. Not long after her arrival in California, Chien-Shiung learned of the Japanese invasion of China, which affected her family’s hometown. She would not hear from her family for eight long years. After she completed her PhD, she was considered ‘the authority‘ on nuclear fission, according to Robert Oppenheimer. Renowned physicist Enrico Fermi even consulted her for advice on how to sustain a nuclear chain reaction in the making of the atomic bomb.

For decades, physicists had assumed that, there was no way to differentiate left from right according to quantum mechanics. Quantum mechanics is the theoretical underpinning of modern physics that successfully describes the behavior subatomic particles. The assumption that left and right were indistinguishable was known as ‘parity symmetry’. It was naturally appealing, much like symmetries that exist in art, biological organisms, or other natural phenomena, like snowflakes.

https://www.flickr.com/photos/chaoticmind75/6922463361

Zoomed-in image of a snowflake. When Mme Wu awaited the train that Christmas Eve, she was surrounded by snowflakes, a reminder of how symmetry is ubiquitous in the natural world. Such symmetries stood in stark contrast to the discovery she was about to announce.

Nonetheless, the idea of this symmetry was called into question at a scientific conference in 1956. Within that same year, Chien-Shiung Wu would demonstrate in her lab at NIST that parity was violated for particular types of decays. In other words, these decay processes did not look the same in a mirror. This discovery was far from Chien-Shiung Wu’s only claim to fame.

Wu made many advancements in beta decay, which is the disintegration of a neutron that results in the emission of an electron and another particle called a neutrino. It was eventually with the beta decay of the element cobalt-60 that she ran her famous parity violation experiment. Using a magnetic field and low temperatures, she was able to achieve the parity violation results that turned the world on its head.

Chien-Shiung Wu did not receive the Nobel Prize, though her two male theorist colleagues did. In spite of this oversight, she obtained recognition in other ways. She was the first female physics instructor at Princeton University and the first female president of the American Physical Society (APS). Her success can be partially attributed to her parent’s encouraging attitude towards women’s education. Fortunately, they survived the Japanese invasion during World War II, with her father engineering the famous Burma Road. C. S. Wu ushered in an entirely new era in which other assumed symmetries would be overturned, helping us to more deeply understand the state of the universe that we see today.

Peer edited by Kaylee Helfrich.

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Underground Science at SNOLAB

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The best models of how our world works are incomplete. Though they accurately describe much of what Mother Nature has thrown at us, models represent just the tip of the full iceberg and a deeper understanding awaits the endeavoring scientist. Peeling back the layers of the natural world is how we physicists seek a deeper understanding of the universe. This search pushes existing technology to its limits and fuels the innovation seen in modern day nuclear and particle physics experiments.

https://www.flickr.com/photos/colinjagoe/5247835812

This is a map of the SNOLAB facility. It’s 2 km (~1.2 miles) underground and is the deepest clean room facility in the world!

Today, many of these experiments search for new physics beyond the Standard Model, the theory physicists have accepted to describe the behavior of particles. Some physical phenomena have proven difficult to reconcile with the Standard Model and research seeks to improve understanding of those conundrums, particularly regarding the properties of elusive particles known as neutrinos which have very little mass and no electric charge, and dark matter, a mysterious cosmic ingredient that holds the galaxies together but whose form is not known. The experiments pursuing these phenomena each take a different approach toward these same unknowns resulting in an impressive diversity of techniques geared towards the same goal.

On one side of the experimental spectrum, the Large Hadron Collider smashes together high-energy protons at a rate of one billion collisions per second. These collisions could have the potential to create dark matter particles or spawn interactions between particles that break expected laws of nature. On the other side of the spectrum, there is a complimentary set of experiments that quietly observe their environments, patiently waiting to detect rare signals of dark matter and other new physical processes outside the realm of behavior described by the Standard Model. As the signals from the new physics are expected to be rare (~1 event per year as compared to the LHC’s billion events per second), the patient experiments must be exceedingly sensitive and avoid any imposter signals, or  “background”, that would mimic or obscure the true signal.

The quest to decrease background interference has pushed experiments underground to cleanroom laboratories setup in mine caverns. While cleanrooms reduce the chances of unwanted radioactive isotopes, like radon-222, wandering into one’s experiment,  mines provide a mile-thick shield from interference that would be present at the surface of Earth: particles called cosmic rays constantly pepper the Earth’s surface, but very few of them survive the long journey to an underground lab.

Figure reproduced with permission from Michel Sorel from La Rivista del Nuovo Cimento, 02/2012, Volume 35, Issue 2, “The search for neutrinoless double beta decay”, J. J. Gómez-Cadenas, J. Martin-Albo, M. Mezzetto, F. Monrabal, M. Sorel, all rights reserved, with kind permission of Società Italiana di Fisica.

The rate at which muons, a cosmic ray particle, pass through underground labs decreases with the depth of the lab. At the SNOLAB facility, shown in the lower right, approximately one muon passes through a square centimeter of the lab every 100 years.

The form and function of modern underground experiments emerged from the collective insights and discoveries of the scientific community studying rare physical processes. As in any field of science, this community has progressed through decades of experimentation with results being communicated, critiqued, and validated. Scientific conferences have played an essential role in this process by bringing the community together to take stock of progress and share new ideas. The recent conference on Topics in Astroparticle and Underground Physics (TAUP) was a forum for scientists working to detect dark matter and study the properties of neutrinos. Suitably, the conference was held in the historic mining town of Sudbury, Ontario, home to the Creighton Mine, at the bottom of which lies SNOLAB, a world-class underground physics laboratory which notably housed the 2015 Nobel Prize winning SNO experiment. SNO, along with the Super-Kamiokande experiment in Japan’s Kamioka mine, was awarded “for the discovery of neutrino oscillations, which shows that neutrinos have mass.”

There is a natural excitement upon entering an active nickel mine, donning a set of coveralls, and catching a cage ride down into the depths; this was our entrance into the Creighton Mine during the TAUP conference. After descending an ear-popping 6800 feet in four minutes, we stepped out of the cage into tunnels— known as drifts— of raw rock. From there, we followed the path taken everyday by SNOLAB scientists, walking approximately one kilometer through the drifts to the SNOLAB campus. At SNOLAB, we prepared to enter the clean laboratory space by removing our coveralls, showering, and donning cleansuits. Inside, the rock walls are finished over with concrete and epoxy paint and we walked through well-lit hallways to a number of experiments which occupy impressively large caverns, some ~100 feet high.

Photo credit: Tom Gilliss

Physicists visiting SNOLAB get a close-up view of the DEAP-3600 and MiniClean dark matter experiments. Shown here are large tanks of water that shield sensitive liquid argon detectors located within.

Our tour of SNOLAB included visits to several dark matter experiments, including DEAP-3600 and MiniClean, which attempt to catch the faint glimmer of light produced by the potential interaction of dark matter particles with liquid argon. A stop by PICO-60 educated visitors on another captivating experiment, which monitors a volume of a super-heated chemical fluid for bubbles that would indicate the interaction of a dark matter particle and a nucleus. The tour also included the SNO+ experiment, offering glimpses of the search for a rare nuclear transformation of the isotope tellurium-130; because this transformation depends on the nature of neutrinos, its observation would further our understanding of these particles.

SNOLAB is also home to underground experiments from other fields. The HALO experiment, for instance, monitors the galaxy for supernovae by capturing neutrinos that are emitted by stellar explosions; neutrinos may provide the first warnings of supernovae as they are able to escape the confines of a dying star prior to any other species of particle. Additionally, the REPAIR experiment studies the DNA of fish kept underground, away from the natural levels of radiation experienced by all life on the surface of Earth.

The search for rare signals from new physical phenomena pushed physicists far underground and required the development of new technologies that have been adapted by other scientific disciplines. The SNOLAB facility, in particular, has played a key role in helping physics revise its best model of the universe, and it can be expected that similar underground facilities around the world will continue to help scientists of many stripes reveal new facets of the natural world.

Peer edited by JoEllen McBride and Tamara Vital.

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Talking Science with Grandma: How to Communicate Science to the Public

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Before we know it, it will be summer.  That means sunny days, flowers, barbecues, beach trips, and family reunions.  With family reunions comes having to explain to every cousin, aunt, uncle, and grandparent what it is that you actually do while you’re conducting research.

https://www.flickr.com/photos/eryoni/2875567642/in/photostream/

Family reunions at the park can often lead to confusing explanations of your research!

At one of these family functions, my grandma asks “So how’s your research going?”  

I tell her that my research is going well and I am writing a paper for publication in a scientific journal.  She responds with “That’s fantastic sweetie! What is the paper about?”

I tell my grandma that my article is about germanium nanowires with unique electronic and phononic properties that have generated new interest in their use for electronics and space technologies. My work investigates how energy is converted to coherent acoustic phonon propagation within germanium nanowires using ultrafast pump-probe microscopy.  

Grandma politely nods as I talk and then says “those bugs sound interesting.”  Where did the “bugs” come from? Nanowires are not bugs.  Clearly, there was a disconnect somewhere.  

Why is effective science communication important?

Publishing is essential in order for a scientist to have a successful career.  But publishing comes in many forms: scientific journal articles, news releases, social media posts, etc.  At the center of this is being able to communicate our research to others.  As scientists, we need to focus on engaging our audience, and before that, take the time to consider who is in the audience.  Are we talking to other scientists in our niche field, scientists in another area, or the public (like Grandma)?  By leading my research summary with the details of my experimental methods, the audience gets overwhelmed with jargon and details.  What the general public really wants to know is the main result and why they should care.

How to Communicate Science to the Public:

  1. Determine the goal for communication: are you trying to influence decision-makers, humanize scientists, build trust between the public and scientists, etc?
  2. Engage the audience: with whom are you communicating and what motivates the audience? Tell a story, ask a question, find commonalities.
  3. Determine the message: think about the most important result that you want the audience take away from your talk.  Quality before quantity.

I should have explained my science like this:

I went to my first country concert in Raleigh, NC and saw Lady Antebellum, Hunter Hayes and Sam Hunt.  The way the bands played their guitars was beautiful. You could feel the passion and sound waves rolling through the Amphitheatre.  

In my research, we basically build and play “nano-guitars”.  Germanium nanowires, wires that are about 60,000 times thinner than a single human hair,  are suspended over tiny trenches, similar to the strings across an acoustic guitar.  I use a laser, like a musician uses a guitar pick, to make vibrations (sound waves) in the nanowires and watch them travel along the wire. In guitars, the frequency or pitch of the sound wave is determined by the thickness, length, elasticity, and tension of the strings. The same thing happens with the germanium nanowires, changing the diameter of the nanowire changes the frequency of the vibration.

Image created by Kelsey Brereton

Photons hit the nanowires and launching vibrations. Essentially, this is a nanoscale acoustic guitar!

By studying the vibrations and how they travel through a nanowire, we learn how elastic (flexible or resilient) materials are as they shrink to the nanoscale. With this information, we could design new electronics that use vibrations to learn more about the world and universe we live in.

Want to develop the skills to communicate science to a general audience? Check out these upcoming workshops at UNC!  

Creatively Engaged Conversations – Methods of Communicating Your Research to Different Audiences will be held on  Monday April 24, 2017 at 11:00 am – 1:30 pm at Wilson Library Room 504 (on 1st floor of library near grand entrance) Register: http://tinyurl.com/mlvrgj7

SWAC Writing Workshop: The writing workshop is the final event in the SWAC seminar series and the opportunity for you to workshop your own science piece for general audiences. Whether you’ve started a blog post and want a chance to polish it or are interested in writing but are not sure where to start, you are invited to come get feedback from peers and science communication experts from around the Triangle.

Writing Workshop Part 2, Thursday, April 27, 2017 3-5 pm: http://tinyurl.com/z2o8ugl

Peer edited by Tom Gilliss.

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Cold, What Is It Good For?

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https://pixabay.com/en/woman-girl-winter-cold-person-1024998/Winter is officially still three weeks away, although the alternating 30° F nights and 75° F days makes that difficult to remember. The arrival of winter means that it is less pleasant to be outside, there are fewer hours of sunlight, and it is harder to get out of bed in the morning. Most Southerners don’t really enjoy the winter. But here are three ways really cold temperatures actually help physicists in their quest to understand nature.

Stargazing

Some telescopes must go to the extreme cold in Antarctica. The South Pole Telescope is recording some of the first light from the universe. This light, called the Cosmic Microwave Background, contains clues to help astronomers understand what makes up the Universe and how that has changed over time. The high altitude and low temperatures in Antarctica make it possible to see these radio waves, as there is less water vapor present in the atmosphere to absorb them when compared to other regions. For a fascinating account of what it is like to work with the South Pole Telescope, check out Keith’s blog from his time there.

For most observatories, the best observing conditions occur during the winter. This is primarily because the air is less turbulent. Heat from the earth rises up at night during the summer months, creating a more turbulent atmosphere. This causes stars to appear more blurry. But during the winter, the ground is cooler, so there is less turbulence at night. However, most observatories experience more extreme weather during the winter, somewhat limiting how often astronomers can utilize the best conditions.

The colder weather is a great reason to go to a star party over the next few months. For people living in the Triangle, the Morehead Planetarium teams up with the Chapel Hill Astronomical and Observational Society to stargaze about once a month at Jordan Lake. You can see the full schedule here.

Quantum Mechanics

When you think about how things move and interact, you are most likely pondering what physicists refer to as classical mechanics, the motion of relatively large things. But quantum mechanics deals with how tiny, individual atoms and particles move and interact with their environment. However, quantum mechanics is difficult to study because atoms move quickly at room temperature. When the temperature drops, though, atoms lose energy and slow down. This enables physicists to study some of the strange quantum mechanical properties of atoms. For example, at temperatures around -459° F, individual atoms can gather together and begin acting collectively like a single atom. At the coldest possible temperature, known as absolute zero (-459.6° F), atoms lose all their energy and stop moving. This phenomenon of particles acting as a group only occurs close to absolute zero, forming a state of matter known as a Bose-Einstein condensate. First created in a laboratory in 1995 and winning the Physics Nobel Prize in 2001, Bose-Einstein condensates help physicists study some of the strange quantum mechanical properties of atoms and how they interact in extreme conditions.

The Large Hadron Collider

http://cds.cern.ch/record/1211045

The Large Hadron Collider at CERN. Image credit: CERN

The Large Hadron Collider (LHC), a 16.7-mile long particle collider on the border of France and Switzerland, operates at -456° F, slightly warmer than the temperature required for Bose-Einstein condensates. Before colliding, particles can travel around the ring thousands of times. To keep particles along the track before colliding, the LHC uses strong magnetic fields generated by superconducting materials. Electric current is required to make the magnetic fields, which often generates heat (think of how cell phones heat up during charging). Superconducting materials, instead, create very little heat when cooled down to very low temperatures, creating the right conditions for physicists to use them at the LHC. These conditions enable the LHC to investigate the building blocks of nature.

So the next time you are fretting over the cold, perhaps you can remember the physicists who need the cold to make discoveries happen.

Peer edited by Lindsay Walton and Manisit Das.

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The Physics Behind the Newest OK Go Video

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I first heard of the band OK Go when they released their music video for ‘Here It Goes Again,’ which features the band members cruising back and forth over treadmills. I soon discovered that many of their other music videos are equally captivating and involve cool applications of physics. For example, their video for ‘This Too Shall Pass’ involves an elaborate Rube Goldberg machine, a complex device designed to perform a simple task. This is the same type of device the kids use in ‘The Goonies’ to open the gate for Chunk.

A few weeks ago, they released the video for their song ‘Upside Down & Inside Out,’ which might be the most fun so far. This video involves the band members floating about in an airplane like astronauts. Go ahead and watch it, then continue below and I will explain some of the physics behind the video.

How They Did It

The flight path of aircraft

The flight path of aircraft simulating weightlessness. Image credit: NASA

First of all, the members of OK Go are not in space or in zero gravity. They are in a plane flying at altitudes similar to commercial aircraft. This plane, however, flies in parabolic trajectories, as shown in the figure, to simulate weightlessness within the plane. NASA has a similar plane called the Weightless Wonder to help astronauts train and perform science experiments. The figure to the left shows how this works. As the plane starts to fly higher, everything on board feels heavier than normal (0-20 seconds in the image). Once the plane reaches a certain altitude, the pilots slow down the engines and the plane begins to move only under the influence of gravity (20-45 seconds in the image). This is just like what happens when you throw a ball into the air. You apply a force to throw the ball, but once it leaves your hand, it moves only under the influence of gravity. It goes up a little ways before coming back down.

In the OK Go video, the people and objects inside the plane are like the ball thrown into the air. But since the people are moving at the same rate as the plane, it simulates weightlessness. You do not feel this way when you skydive, for example, because you can feel the air pushing on you as you fall down. Inside the plane, however, you feel weightless because the air is falling at the same rate as you.

Typically, these parabolic trajectories that create weightlessness can only last up to about 30 seconds. For a song that is 3:21 long, this means OK Go had to shoot the video in multiple segments and then edit it to make it look smooth. You can see that at certain times everything falls to the floor of the plane (most obvious at 2:03, 2:27, 2:46, and 3:08). At these moments the plane is coming out of the parabola so gravity is, in a way, turning back on. OK Go released a short video describing some of the challenges they faced filming in this type of environment and how they solved those problems.

 Other Neat Physics

This whole video is full of great examples of introductory physics; I bet many teachers are already writing questions based on this video. Here are three of my favorite parts of this video from a physics point-of-view.

  1. One of the coolest visual aspects of the video is at 2:51 when the balloons full of paint appear. The band members start popping the balloons and paint goes everywhere. On Earth, if you pop a balloon full of anything, the contents are going to fall straight down to the ground. But in weightlessness, the direction the paint goes depends on a few things.
    The lead singer first pops a purple balloon with orange paint that he holds in his hand. He takes his finger, pushes almost straight down to pop the balloon and the orange paint moves upwards. It moves up because of the conservation of momentum. Since the balloon is stationary and his hands moves downwards, the paint goes up. In the same situation on Earth, the paint would try to go up as well. But the effect of gravity is strong enough to overcome this motion and would force the paint to fall to the ground.
    You have experienced something similar to this if you have ever tried to push someone while rollerblading or ice skating. If you are standing still and give someone a push, you will start moving the opposite way.
  2. At 1:38 the flight attendant in front starts spinning with her legs out before bringing them in and spinning more quickly. She is conversing her angular momentum, which is exactly the same thing ice skaters do when they spin.  If you are spinning and have your arms out you will spin faster when you bring them in, and vice versa. You can do this in most office chairs too, but it is helpful to have a friend spin you.
  3. Disco balls are released around 2:37. You can see a couple of them bouncing off each other and all of them hit the walls of the airplane. Just like in the game of pool, the direction they each travel depends on the speed and direction of the collision. Calculating the trajectories of pool balls is a common physics question. Calculating the trajectories of the disco balls would be a fun extension of that.

Like most OK Go videos, this one took a lot of work to put together. They have released a few videos detailing how it all came together. This band keeps finding ways to include great physics demonstrations in their videos.

 

Peer edited by Kayleigh O’Keeffe & Ashley Fuller

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Biology and Physics Meet in the Middle

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Scientists thrive on “aha” moments— breakthroughs in knowledge that come from careful planning or perhaps fortuitous luck. For a team of researchers led by Josh Lawrimore, a fourth-year graduate student in Kerry Bloom’s lab at UNC, their “aha” moment came about by approaching their research question in a new way.

Josh’s research is focused on what happens to a chromosome—a long molecule of DNA wrapped around proteins—when a parent cell divides into two daughter cells. To study chromosomes, the Bloom lab uses baker’s yeast as an experimental model. The centromere region in yeast cells has been well-studied, and their chromosomes are similar in structure to human chromosomes. Amazingly, through working with this simple organism, Josh has solved a long-standing mystery in the field of cell biology.

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