Fire a laser at it!

by Howard Yu

If you’ve ever seen a Star Wars or Star Trek movie, you’re familiar with the concept of a laser, a word that conjures images of fantastic sci-fi space battles. But lasers are no fantasy – they’ve thoroughly infiltrated everyday life, and are used in everything from barcode scanners and DVD drives to industrial cutting, surgery, and of course, scientific research. How do lasers work, and how do we use them in research? I’ll try to address those questions here.

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Truly we live in the future.

Before I talk about lasers, I need to talk a little about light. Physicists use the term “light” to refer to all electromagnetic radiation, which includes the visible light that we see as color, but also things like radio waves, microwaves, and x-rays. Light behaves both like a wave and like a particle, and the individual light particles are called photons (the idea of light as particles originated with Einstein, and is actually the work for which he won the Nobel Prize).

The word “laser” originated as an acronym, standing for light amplification by stimulated emission of radiation. Essentially, lasers consist of an energy source, a gain medium, and an optical resonator. The gain medium is what makes it possible to generate the laser beam and determines the color of the light produced; this is what people are referring to when they say, for example, “HeNe laser” (say hee-knee). In that case, the gain medium is a mixture of helium (He) and neon (Ne) gas, which produces a red beam. Lasers can be made with many different gain mediums, including dyes, gasses, and solids. First, the energy source generates the first few photons to get the laser started. The photons pass through the gain medium, and each photon interacts with the medium and has a chance to produce another photon traveling in the same direction as the original. This is why the word “gain” is used, because you start with one photon and end up with two. Finally, the optical resonator – at its simplest a pair of mirrors at either end of the laser – passes the photons back and forth through the gain medium, so that each photon produces many additional photons before escaping the resonator. This process results in a steady stream of highly coherent photons.

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Basic design of a laser – in this case, the flashlamp provides the energy source, the Nd:YAG crystal is the gain medium, and the two mirrors form the optical resonator.

The feature that distinguishes a laser from other light sources is the laser’s coherence. Unlike, say, a light bulb, a laser produces light that is almost completely the same color.  (The color of light is determined by its wavelength. Wavelengths of visible light range from about 400 nm to 750 nm – see Andy Berger’s post for an idea of how small that is.) Lasers can be made with a wide variety of wavelengths, ranging from 150 nm to over 1 mm. Different applications have different wavelength requirements – for example, optical disc drives use lasers to read information off of CDs, DVDs, and now Blu-ray discs. The reason Blu-rays can store more data than CDs or DVDs is because the laser used to read the disc is blue, hence the name.  Specifically, Blu-rays use 405 nm light, while CDs and DVDs use 780 and 650 nm respectively.

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Spectrum produced by a fluorescent lamp (left) and by a HeNe laser (right).

Lasers also produce spatially coherent light, by which I mean a laser generally sends photons only in the direction it is pointing. The light from any source will spread out, and lasers are no different (and different lasers will spread at different rates). However, the beam from a flashlight or spotlight will spread out much more quickly than a laser, and we can use various optics to make a laser beam spread very little over long distances (a process called collimation), something that’s only possible because of the laser’s coherence. Even a spotlight is only visible from up to a few miles away, while you could aim an ordinary, well-collimated laser in San Francisco at the Empire State Building and the spot would be maybe a single story tall, so still easily visible (assuming you didn’t hit any mountains along the way). A side effect of this is that you should not be able to see a laser beam if you are not looking right down the beam path, as there simply isn’t any light for your eye to see. When you can see the beam, it’s because some of the light is scattering off particles in the air.

There are a wide variety of measurements you can do with a laser. In our lab, we have a titanium-sapphire laser (Ti:Sapph) that can output about 2 watts of power. We use our laser to investigate different materials properties – one of the basic measurements we do is to just hit a sample with the laser and see what light comes back out. Another measurement that I do is to reflect the beam off of a sample to do a sensitive measurement of its magnetic behavior.

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The inside of our laser (left) and the optical table in our lab (right).

You can see the table has a grid of holes that we use for a variety of equipment, most commonly lenses and mirrors to focus and steer the laser beam. Something we have to keep in mind is that the absolute power of the laser is often not as relevant as the power density. We can focus a laser down to very small spots (about 100 microns in our lab), so the amount of power the laser delivers is also focused into a small area. It’s like using a magnifying glass to start a fire, a staple of survival movies. A typical incandescent light bulb consumes 60 watts of power, which it converts into light and heat (an incandescent bulb is actually much better at producing heat than light). If a laser output that much power and was focused to a 100 micron spot, the power density would be high enough to cut through steel (I have a couple of shirts with holes in them from laser damage).

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Kind of like this. (Goldfinger, 1964)

It’s hard to believe that when they were invented, lasers didn’t have any obvious purpose – they were a solution in search of a problem, a toy for scientists to play with. Today, they’re widely used in both commercial and research applications, from more mundane uses like laser pointers to out-of-this-world uses like igniting nuclear fusion. It just goes to show that as a scientist, you never know when the experiment you’re slaving over could someday affect the lives of millions of people around the world.

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About Howard Yu

ahowardI’m a senior graduate student in Professor Zeke Johnston-Halperin’s lab at OSU. I was born and raised in California, but chose to come to Ohio anyway. In my free time, I read a lot of books, watch a lot of movies, and play soccer and basketball. After graduating, I hope to work in public policy.

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Aren’t You Just a Biologist?

by Morgan Bernier

Biophysics is one of the fastest growing occupations according to the Bureau of Labor Statistics, though most physicists often hesitate to call it “real” physics.  “Aren’t you just a biologist?” my friends ask, “How is mixing one clear liquid into another clear liquid physics?”

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Mixing samples for my experiment.

It’s true that I’ve spent 90% of my graduate school career using biochemical techniques to prepare my biological samples (more on these later) but, like other physicists, I am ultimately trying to measure physical quantities: energies, forces, and motion of matter.

I am a physics graduate student at The Ohio State University with an undergraduate degree in physics (from Miami University in Oxford, Ohio).  I have not taken any biology or chemistry classes since high school.  I spent the first few years of graduate school teaching myself all of the biology and chemistry I need for my experiments, and I’m still learning new things today.  Mastering completely new lab techniques that most physicists will never do is actually a lot of fun.

At Ohio State, I work in Dr. Michael Poirier’s biophysics lab.  We study how DNA is organized and compacted by proteins inside the cell nucleus.  DNA contains all of the information for how our bodies look and function, and we have nearly 2 meters (about 6 feet) of DNA in each of our cells.  Organization and compaction of the DNA is necessary for all of it to fit inside our tiny cells, so our cells wrap the DNA around protein molecules called histones into what look like little spools of thread.  These DNA/protein spools are called nucleosomes.

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An image of a small section of DNA wrapped into nucleosomes taken using an atomic force microscope by a former graduate student in our lab, Marek Simon. This type of microscope allows us to see things that are too small to see under a regular light microscope.

By wrapping the DNA into nucleosomes, the DNA becomes more compact and is protected from damage.  My samples usually consist of a single nucleosome, so that I can observe the physical interaction between the DNA and the proteins.

Our lab is broken up into two physical areas: the biochemistry lab and the physics lab.  I spend most of my days in the biochemistry lab making my DNA/protein samples.  Thankfully, I have helpers, millions of them actually.  We program E. Coli bacteria to make our DNA and proteins, so part of my job involves carefully growing E. Coli bacteria.  Sometimes this means that I have to come into the lab in the middle of the night to check on them.  I can’t be sure, but I think singing to them helps.

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The biochemistry lab (left) and the physics lab (right).

E. Coli bacteria are typically associated with food poisoning from contaminated meat, but they are also found in your intestines and help you digest your food.  We use E. Coli because they reproduce very quickly (about once every 20 minutes), and we can easily program them to produce DNA and proteins that are usually found in other organisms like frogs and mice.  By using E. Coli, we don’t have to sacrifice frogs and mice for our science.

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Agar plates growing E. Coli bacteria. These particular ones were used to produce DNA. These plates are about the size of the palm of your hand. The streaks you see are colonies of E. Coli bacteria growing. Each streak contains thousands of individual E. Coli bacteria.

So where does the physics come in?  Once I have my nucleosome sample, we use a microscope equipped with lasers to look at them.  The lasers are used to excite dyes on our samples, so that we can see them and observe dynamics of our DNA-protein structures.  I think the coolest part of this experiment is that because the dye molecules are so bright, we can see individual DNA molecules with proteins fluctuating on our slides.  The down side is that I end up spending hours in a dark room watching little blinking dots on a screen.  That is how research is though. Some days can be pretty boring, but other days, when your experiment is working, you are observing something no one has ever seen before.

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Microscope slide containing our sample on the stage of our microscope where we do our experiments. The green light is from a laser that we shine onto our samples to illuminate the dye molecules attached to our bio-molecules.

One of the best parts of biophysics is that it is highly interdisciplinary.  In my research I work with biochemists, mechanical engineers, chemists, materials scientists and occasionally other physicists.  I get to meet graduate students from other departments at Ohio State, but also from other universities and sometimes other countries.  Sometimes I work in their labs and sometimes they work in ours.  There are some days that our lab is busier than the cafeteria at lunch time.  I am a very social person, so I love having someone to talk to while I work.  With so many people in the lab, it’s hard not to have a little fun.

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We have a freezer in our lab that is at -80 degrees Celsius (-112 degrees Fahrenheit) to store protein, DNA and E. Coli cells for long periods of time. The freezer accumulates a lot of snow and ice, so one day while we were cleaning it, we decided to make a snowman.

Scientific research isn’t all fun and games, but it isn’t boring all of the time either.  We work pretty hard most days, but being able to observe single molecules is really cool.  I am very happy that I decided to become a biophysicist whether it’s ‘real’ physics or not.

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Poirier Lab at our yearly summer picnic. I am in the front row, third person from the right.

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About Morgan Bernier

MorganpicI am a 5th year graduate student doing experimental biophysics at The Ohio State University.  In my spare time, I enjoy running, hiking and camping with my husband, Dan, and our dog, Indiana.  Our cat doesn’t really behave that well on a leash.  When I graduate, I hope to conduct research in the biotech industry and someday start my own company.

5 Highlights of My Summer REU at the University of Wisconsin – Madison

by Brittney Curtis

REU (Research Experience for Undergraduates) programs are a way for students to get involved in scientific research while in college. They typically take place over the summer at universities and national labs across the United States. Participants get to travel to another location to work on their REU project, and they are provided housing and a small stipend for the duration of the program. Students interested in science that do not have research opportunities at their home college (some small liberal arts colleges, for example) are especially encouraged to apply for REUs.

Last summer I stayed at Ohio State to do research in the Department of Astronomy through a program called the Summer Undergraduate Research Program (SURP). You can read about my research experience at SURP here. This summer I traveled to the University of Wisconsin – Madison to participate in the REU program in their astronomy department, and it was a whole different experience. Here are five ways that I made the most of my summer research experience in Madison.

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The 2013 UW – Madison Astrophysics REU participants on a field trip to Yerkes Observatory. in Williams Bay, WI

1. Getting to know my fellow REU students

The people I spent the most time with over the summer were the 8 other REU students at UW – Madison. I got to know them on a professional level and a personal level. Most of us shared a working space in the undergraduate computer lab in the astronomy department, so we helped each other with programming problems and unfamiliar concepts at work every day. We were all housed on the same floor of an apartment complex near campus, so we hung out after work as well, watching movies and preparing group meals. The other students were all incredibly friendly, hard-working, and excellent researchers. Astronomy is a small field, so I’m sure our paths will cross again in the future, and I look forward to it.

2. Discovering new ideas in astronomy

My REU project was about the properties of galaxies that are thought to host extensive gas outflows and accretion, a topic that I knew almost nothing about at the start of the program. I had to do a great deal of reading and ask a lot of questions to get up to speed, but in the process I learned a lot of new ideas and methods in astronomy. In retrospect, I’m happy that I got to work on something completely unfamiliar to me, because the REU wouldn’t have been such a huge learning experience for me otherwise.

Starting on a new project also gave me the chance to consistently practice better research habits. I kept a journal of notes about my research methods, and kept track of the hours that I worked. I learned how to program in Python, which is a widely-used programming language in astronomy. All of these new ideas and skills that I learned will help me be a better student and researcher in graduate school and beyond.

3. Exploring the beautiful city of Madison, Wisconsin

Madison is a gorgeous city situated in between two big lakes, called Lake Monona and Lake Mendota. The university is on the lakefront of Mendota, where local residents swim and sail during the warm summer months.

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A view of Lake Mendota at dusk from the Washburn Observatory on campus.

On Friday afternoons there were public concerts at the Memorial Terrace overlooking the lake, and every Saturday morning was the Farmer’s Market at the Capital Square featuring local produce and cheeses. I tried Wisconsin cheese curds, both the fresh and the deep-fried variety, and they were delicious. I also spent a lot of time window shopping on State Street, a cute pedestrian street lined with tons of little shops and restaurants, which leads from the university to the Capital Square.

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The Memorial Terrace on a Friday afternoon.

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Walking down State Street towards the Capital Square.

One of my favorite places to hang out was a coffee shop down the street from our apartment complex called Indie Coffee. I went there on Sunday afternoons to catch up on my summer reading list and eat brunch. They had amazing waffles!

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The Red & White Waffle at Indie Coffee.

4.  Participating in public outreach

Outreach is particularly important to me as an aspiring scientist because I think it’s valuable to promote public interest in science and public understanding of science. During my summer in Madison, I had the opportunity to volunteer for a public outreach program called Universe in the Park (UitP).

UitP was created by the Department of Astronomy at UW – Madison to teach the public about astronomy. Every summer they go to state parks throughout Wisconsin (where the sky is dark) and give a short presentation about a topic in astronomy, and then they set up telescopes for the public to view astronomical objects. As a UitP volunteer I got to travel to Wildcat Mountain State Park and show campers at the park what Saturn looks like through a telescope. We could see the rings and some of the larger moons very distinctly. I also answered questions about different stars and constellations, and a few questions about my summer research project. Doing public outreach has helped me learn how to better explain scientific ideas to people that don’t have a background in science.

5. Getting to know the scientists at UW – Madison

Everyone in the Department of Astronomy at UW – Madison went out of their way to get to know us and make us feel welcome over the summer. My research mentor, Dr. Britt Lundgren, was exceptionally nice and approachable, and I loved working with her. She gave me tons of advice about my research and about my career path, and was always helpful when I ran into problems with my project. The graduate students invited us to their social events and gave us advice about preparing for graduate school, and the other professors and scientists gave us advice about research and the job outlook in astronomy. It gave me a positive outlook on the culture of the field to experience how friendly and welcoming everyone was. I’m very grateful to the Department of Astronomy at the University of Wisconsin – Madison for hosting me this summer, and for making my experience both fun and a valuable learning experience.

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About Brittney Curtis

I am in my fourth year as an undergraduate studying physics and astronomy at The Ohio State University. I grew up in the beautiful coastal mountains of Oregon but moved to the midwest for college. Outside of class, I serve as President of the Society of Physics Students and Vice President of the Astronomical Society at OSU. I also love to read science fiction in my spare time. After I graduate from Ohio State, I plan to work towards a PhD in astronomy. Feel free to contact me by leaving a comment!

First Job’s the Charm

by Alexander Speirs

“Choose a job you love, and you will never have to work a day in your life.” This is one of the few Confucius sayings with which I can fully identify. Although I suppose I’m not actually the best judge on that front, as I have only had jobs in academia throughout my life. The closest I’ve had to a “regular” work is tutoring during high school along with some volunteering and extracurricular organizational work. Straight out of high school I began an internship funded by the National Science Foundation with Dr. Roland Kawakami’s group at the University of California, Riverside (UCR), and I have simply never stopped working in research.

KGroupHike

The Kawakami Group at Mt. Rubidoux in Riverside, California. Dr. Roland Kawakami is in the middle of the top row and I am to the far right in the bottom row.

To clarify, the positions I’ve held, both at The Ohio State University and at UCR, fall into the category of experimental condensed matter physics research, which is a fancy way of saying we study materials, ranging from your standard metals (iron, copper, nickel, etc) to the novel two-dimensional sheet of carbon called graphene. Now, “What’s so great about this gig?” you might ask. Physics, and other more math-centric scientific concentrations (engineering, computer science, etc) depend more on application and evolution of knowledge, as opposed to memorization and technique. I prefer it this way, it makes being bored a rare occurrence. When you are working on a specific project, it is normal that the methods and even the goals change as you go, and the results are often quite beautiful.

IMAG0360

Part of my summer project at OSU, acid-etched silicon wafers resulting in a vibrant rainbow pattern.

One of the main factors keeping me interested in this profession is the constant evolution that other jobs seem to lack. I often feel slightly left out when I hear friends and colleagues discussing past jobs and experiences, however I can’t imagine myself enjoying any other job. My understanding is that most “normal” jobs, such as clerical, retail or restaurant positions, involve extremely repetitive tasks or routines. In my 2 years working at UCR’s Nanoscale Spintronics Laboratory, the closest I came to having a routine was regularly producing graphene samples, and even then there were constant changes from problems cropping up, improvements being made and needs evolving. This constant adaptation is the way of things when you are working on scientific research, as our work generally does not extend beyond a fundamental understanding. I (and most scientists) are like children in this way, we tend to be distracted by shiny new things, almost never being involved in application phases. I would like to be able to give a run-through of what an average day of work is for me, but the truth is that I never have an average day. As an undergraduate in research, I often shadow graduate students in their efforts, learning and contributing where I can, but their days rarely go as planned either. This is another aspect that makes this path desirable for me: everyone is constantly learning. Even our “boss” (the Professor or Principal Investigator) constantly adapts to new information. For instance, when our vacuum chamber was disabled by a procedure involving reactive gasses, many members of the group, including the Principal Investigator and myself, quickly decided to shift the study and procedure to the furnace system which I was currently working with.

SpinGate

The proposed electronic device for a collaborative project of which my graphene production focused on.

In my spare time, I enjoy building things, from circuits and models to more radical projects such as a ten foot tall trebuchet. This is likely another reason I enjoy my job so much, because it’s similar to my hobbies, but on a much more fundamental level. I like to call many of my projects “big boy Legos”, such as designing and building an extruded aluminum and steel frame to protect us from potential explosions in the lab. Even my graphene production essentially involves stacking carbon and other materials such as metals or semiconductors, but on the atomic scale. One of the main differences is that now I get to play with much more expensive and potent toys. For instance: when moving lab locations at UCR, I was handed one small piece of equipment from our extremely large and complicated vacuum chamber; I was then told that it was worth over twenty thousand dollars. Needless to say, I am very careful around even the most basic looking items in the lab. I also get to work with ultra-high vacuum systems, flammable gases, reactive substances, high voltages and corrosive liquids on a daily basis. I believe that if I were to switch careers, anything else would just seem boring by contrast.

AlFrame

Big Boy Legos: An extruded aluminum frame to enclose the lab’s furnace (upper left).

ExpensiveSource

An example of the expensive component: an atomic hydrogen source. Source: SVT Associates, Inc.

I doubt that I will ever leave the sciences, for a reason told best by Richard Feynman: “You say you are a nameless man.** You are not to your wife and to your child. You will not long remain so to your immediate colleagues if you can answer their simple questions when they come into your office.” There is a definite joy and meaning in simply being able to answer questions and expand knowledge. Despite a certain arrogance that comes from physics being the “purest” science, it is certainly impossible to say that any one person is more knowledgeable than another. In most meetings that I’ve attended, everyone in the room is the resident expert on some aspect, facet or procedure. That sort of identity and importance is very endearing, and leads us to be more productive, more invested in ourselves, the group, and the research. With all of this in mind, I hope to always have a career in this field, it is always interesting and exciting.

**Remember, women are physicists too!

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About Alexander Speirs

BioPicBorn and raised in the desert valley of Riverside, California, I was inclined to stay indoors to escape the relentless heat and sun. I read lots of books, played lots of video games, and watched lots of Discovery Channel. I still do all of these things, but currently my focus is on my undergraduate studies at the University of California, Riverside, and on my research projects as well as my officer position in the student chapter of the Materials Research Society at UCR. I play bass guitar, enjoy cooking, programming, building and blowing things up, and the occasional physical activity (football, frisbee, rock climbing) or beach trip.

A Year in the Life in Physics

by John Campbell

When I chose physics as a major in college, I wasn’t thinking about the paths it might open up for me. I chose it because the material was tough, it allowed me to exercise my fondness for mathematics, and I enjoyed learning about the universe at its most basic level. Eight years later I find myself working on a PhD in nuclear physics, and while all of those benefits are still there, more importantly it has changed the shape of my life and taken me places I wouldn’t have expected otherwise.

Because I can’t do anything the way I’m supposed to, I’ve chosen not to write about A Day in the Life of this graduate student, but to reflect on the past year and some of the great places I’ve gone and experiences I’ve had.

August 2012 – Quark Matter

There are many conferences in the field of nuclear physics, and Quark Matter is the largest. (A quark is a basic building block of nuclear matter. You and everyone you know is made up mostly of quarks.) Last year it was held in a city that’s close to my heart, Washington DC.

I got to meet ‘celebrities’ in the field, well renowned nuclear physicists whom I had previously only known as names at the tops of papers I’d read. I also presented a poster I had designed that explained the motivations of my research and what progress I had made. This involved giving short explanations and answering questions as conference attendees floated around the room browsing mine and all the other posters. It was a great first experience in talking to strangers about my work.  I’m definitely looking forward to next year’s Quark Matter in Germany.

October 2012 – Hot Quarks

Hot Quarks is a very different conference from Quark Matter. It’s much smaller, aimed at giving young scientists in the field a chance to meet each other and communicate without established, well-known physicists looking over their shoulders. It was held in Puerto Rico, and at a time when my native Columbus was just beginning to move from a brisk Autumn to an earnest Winter, the island sun was a welcome change of pace.

It was here that I gave my first prepared talk about my work. There were only about 50 people attending the conference, and the smaller audience and more familiar atmosphere meant I wasn’t very nervous. I got some good feedback and suggestions about what I had done, and met a few other scientists who had projects that were similar to mine.

A week of listening to talks and participating in conference activities can get a little draining, so conference planners usually break up the time with a few fun activities. For instance, we were given a personal tour of the Arecibo Observatory, complete with behind-the-scenes access and some face time with the director. Arecibo is the world’s largest radio telescope, and has been doing amazing science for over fifty years now.

Aricebo is that world’s largest radio telescope. You may have seen it featured in the James Bond movie GoldenEye or the film adaptation of Carl Sagan’s classic Contact.

You may have seen Aricebo featured in the James Bond movie GoldenEye or the film adaptation of Carl Sagan’s classic Contact.

April 2013 – RHIC

In April I traveled to the Relativistic Heavy Ion Collider (RHIC) on Long Island to help run our detector. RHIC accelerates bits of nuclear matter to speeds very close to the speed of light and then smashes them together. The hope is that in studying these high energy collisions we’ll see signatures of how quarks (remember those?) behave and interact.

The three-story STAR detector, where we smash atomic nuclei together to recreate the conditions of the universe just microseconds after the Big Bang. You wouldn’t want to be standing on that scaffolding when they turn the beam on!

The three-story STAR detector, where we smash atomic nuclei together to recreate the conditions of the universe just microseconds after the Big Bang. You wouldn’t want to be standing on that scaffolding when they turn the beam on!

There are two detectors operating at RHIC; I work on the STAR detector (Solenoidal Tracker at RHIC). Instead of being operated by dedicated technicians, scientists in the STAR collaboration (often graduate students and post-docs) take turns handling the day-to-day operations of the detector. You can check out Ken Patton’s post to understand what these shifts are like.  He and I work on vastly different experiments, but the data-taking shifts are a pretty similar experience.

I was training to be the Shift Leader, the person that coordinates the other crew members and communicates with the main RHIC control room. However, at the last minute the actual Shift Leader was called away in an emergency.  As the trainee it was up to me to step in and lead the team, though at this point I had only had one day of training instead of the usual eight.

Here I was–completely unprepared–leading a team of my peers in operating one of the most advanced machines in history to learn about the basic building blocks of matter. This is what made all my work at school worthwhile, this is why I took all those calculus classes. (I’m joking of course; the sheer joy of knowing calculus is why you take calculus classes.)

July 2013 – Stony Brook University

Last month I traveled back to Long Island, but this time to Stony Brook University for the National Nuclear Physics Summer School. This summer school did not have any classroom component or tests at the end. It consisted of four lectures a day, each on a different topic. In between lectures we had ample time to talk about science, meet new people in the field, or just explore the campus.

More than anything else, I came away with a renewed perspective on how diverse the field of nuclear physics is. I usually tell people I’m a ‘nuclear physicist’, but more specifically I study ‘ultrarelativistic heavy-ion collisions’, and in my day-to-day work everyone I interact with does the same. It can be easy to forget that nuclear physics encompasses everything from accelerator physics to medical imaging (X-Ray and MRI machines) to the fusion happening in the sun and other stars. (Nuclear Astrophysics, by the way, is probably the second coolest sounding science subfield I’ve ever heard of, beaten out only by Asteroseismology. Sexy!)

Physics is a breathtakingly rich subject, and the everyday study of the same has been incredibly rewarding. But it is important to remember that for a graduate student like myself, physics is not just a subject of study, but an aspect of my life that takes me to new places and gives me new experiences. More than having published a few papers or being able to solve problems in a textbook, physics has become a part of my culture and personal history. I don’t know what course my life will take after I leave grad school, but I look forward to a life of years as exciting and diverse as the last one.

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About John Campbell

John_juggling

I’m originally a Floridian, and moved to Columbus four years ago to pursue a physics PhD at OSU. Before studying nuclear physics, I meandered through nano-photonics (studying ultrasmall light circuits) and theoretical astrophysics. When I’m not traveling, I write computer code to analyze the mountains of data we take, perform physics outreach, and help with the calibration efforts that keep our detector running smoothly. In my off time I play guitar, juggle, climb trees, and start conversations with strangers.

 

The Program This Week Is … Programming

by Eric Suchyta

As we’ve seen throughout previous postings, a day in the life of a physicist can be quite different from one physicist to another, depending on what kind of physics you do.  However, there are a number of skills that are generally useful and applied everyday across various disciplines.  One such craft is computer programming.  If you’re not too familiar with computer programming, the idea is pretty simple.  You write out a specific set of instructions, and then you tell your computer to go do these actions.  Just like humans speak different languages, there are many different programming languages, each of which has its own strengths and weaknesses.   Programming in each language will look a little different, but at the end of the day they’re all aimed at basically the same thing, helping you tell your computer what to do.

Computer programming is useful to physicists for a variety of reasons.  For one, the problems that physicists attempt to solve are often very sophisticated, maybe so much so that a pen and paper solution alone isn’t even possible.  In such cases we turn to a computer to implement calculations we couldn’t feasibly carry out ourselves.  Also, scientific datasets can be enormous, and often times we need to repeat the same types of analyses over various sets of data.  Humans quickly tire of doing the same task over and over again, but computers love to do this and are much faster at it than we are.  Computer programs are even written to control the instruments themselves when scientists are taking their data.  Some instruments are sufficiently complex that attempting to control each moving part without the aid of computer programs would be utterly impossible.  Take a look below at the picture of the Compact Muon Solenoid (CMS), one of the detectors at the Large Hadron Collider (LHC).  The LHC accelerates protons to extraordinary energies, and this awe-inspiring detector analyzes what is produced following a collision of these high energy protons.  Notice how puny the person (not me) looks compared to the size of it.  Can you imagine attempting to operate something like this without computer assistance?

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One of the detectors at the Large Hadron Collider. Did you notice the person in the center of the picture? Imagine trying to use this detector without any computer aid! Source: CERN

If I tried to share all the ways OSU faculty and students use programming in their lives we would be here for days, so I’ll limit the scope.  Two examples that I find particularly fascinating include biophysicists modeling exactly how DNA functions, and condensed matter physicists moving tiny beads in a controlled way through a magnetic field, which you can watch for yourself in this YouTube video.  For the rest of this post I’ll be sharing my story, focusing on some of the kinds of computer programs I’ve been writing.

My area of specialization is astronomy; I work on a project called The Dark Energy Survey.  If you’ve read the post by Ken Patton, I do the same kind of science he does.  In short, we take lots of images of the sky with an enormous digital camera attached to a telescope, and then analyze the images in order to learn what the Universe is doing on scales roughly 100,000 times larger than the Milky Way.  For a more thorough explanation, I invite you to see our project website or follow this blog written by one of our scientists.  My work for the project has been twofold, writing software for controlling our instruments so that we can efficiently carry out our survey, and writing analysis software that uses our recently acquired data to make meaningful measurements.  In both cases, I’m doing loads of computer programming.  It’d take me a bit too long to adequately describe my analysis software, so I’ll focus on the instrumental side.

We have a very sophisticated camera, and I was responsible for writing applications to control a few of its components.  Today I’ll mention two, called the filter changing mechanism and the hexapod.

The filter changing mechanism does exactly what its name says; it changes filters.  Our camera has six filters to choose from.  Each filter allows the camera to see only one specific color of light, everything else is absorbed.  In astronomy, it is useful to look at the individual colors of the sky as separate images because no two images look the same, and the differences give us clues about what we’re seeing.  I’ve included a picture of the filter changer.  The cartoon version illustrates how it moves the different color filters into the opening, and the frame directly above that is a picture of the real filter changer itself.  To get a sense of how big these filters actually are, look at the next picture comparing the size of this opening to the size of a person.  (Again, I’m not in the picture.)  The scale of our camera is a bit larger than your everyday digital camera to say the least!

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Left: Our camera’s filter changer. The different filters let us look at different colors of light.
Right: We have a huge camera. The filters are the size of this opening.

The hexapod is a system of six “legs” for precisely adjusting the focus of our images.  Again, I included a picture of it (in which I don’t appear).  Despite its massive size, it controls movement of the surface atop those legs with extreme accuracy.  This is where we place our camera, so we can make small adjustments to get the most crisp looking images possible.  To see a much smaller hexapod in action, you can watch this YouTube video.  You can see what I’m talking about at 1:43 into the clip.

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Our camera’s hexapod. The six “legs” can be finely adjusted to control the focus of an image.

Writing programs for such precise and very expensive equipment seemed a bit of a daunting task at first.  Before starting the project I had only had limited programming experience, and had never written anything in Python, the particular language used throughout the work.  In fact, I had never programmed anything before learning some basics in my undergraduate physics courses.  Yet when all was said and done, writing the programs for the camera turned out to be completely manageable.  The instrument has been tested, and much to my delight, what I wrote works!  I’m not quite sure how to explain it, but when you talk to those with programming experience (myself included), there’s a consensus for noticing a genuine feeling of satisfaction when you successfully run a program that you wrote yourself, even if it’s a very simple program.  This feeling is one of the things I look forward to daily at work.  My experiences have also dispelled any misconceptions that I may have had about computer programming.  I assumed it would have been much harder to get the hang of it than it actually was.  With a little effort, anyone can learn to program and open the door to all the applications it affords.  I wish I had learned sooner!

Want to Learn More about Programming?

Although I was taught a small amount of programming in college, the vast majority of what I have learned is self taught.  Introductory programming help is widely accessible online, and this is how many aspiring scientists get started.  I highly encourage you to go this route if you feel inclined.  Googling “<insert programming language here> beginner tutorial” will bring back endless results.  A few programming languages commonly used today include C++, Java, and PythonHere is one website that I know of which offers interactive tutorials.  Another package which introduces you to programming concepts through 3D graphical movement is called ALICE, and is available for free download.

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About Eric Suchyta

michigan_2012_croppedI am entering my fourth year as a PhD student in physics at THE Ohio State University, where I also did my undergraduate degree in physics.  I’m a diehard fan of my local sports teams (Buckeyes, Blue Jackets, Crew, USA soccer), and enjoy playing sports and keeping active in my free time.  I’m into metal music, and I’ve been known to grow a beard every now and then.  I also happen to be an identical twin.  I’m still trying to figure out what I want to be when I grow up.  You can find me on the Twitterverse with handle @eric_suchyta.

When I grow up I want to be a ____

by Anne Benjamin and Megan Harberts

What do you want to be when you grow up?

It’s a question that people are asked from an early age, but one that takes a long time to find an answer for. Even once you pick a major in college you still have lots of options. For example, students that study physics can have careers as researchers, professors, teachers, writers, computer programmers, and even as business people, just to name a few possibilities. Physicists can work at universities, government agencies, non-profit organizations, or private companies.  Private companies are often referred to as “industry.”

To answer the question for ourselves, we (Anne and Megan) have been taking advantage of some of the career exploration opportunities offered by the Center for Emergent Materials at The Ohio State University. In March, we visited the Air Force Research Lab (AFRL, a government lab) at Wright Patterson Air Force Base in Dayton, Ohio, and in May we took a two-day industry trip to Ford Motor Company’s Research and Development (R&D) labs in Dearborn, Michigan.

Like many, but not all, of our fellow graduate students, both of us went directly from high school to college for our bachelors degrees and then straight into graduate school. Because we are both actively doing research for our PhDs at a university, we are familiar with the workings of academic research but only have some idea of what employment at a government lab or in industry might entail.

We do know that there are important differences in how academic, government, and industrial labs direct their research efforts. Modern industry tends to focus on applied research, whereas university and government labs tend toward basic research. Basic research focuses on understanding fundamental science without specific applications in mind, while applied research attempts to meet a specific need or produce a specific product.

We could see the contrast between the two types during our visit to Ford, where we learned that one of their main goals is reducing their environmental impact. They described their research on alternatives to plastic for car interiors, some of which are already standard in their cars.  In comparison, the lab where Anne works at Ohio State currently focuses on exploring the properties and interactions of individual atoms in materials and Megan’s projects attempt to understand and use an organic magnetic material that disintegrates on exposure to air. These experiments are more directed toward our comprehension of materials and their properties than on the products that may result. Our visit to AFRL revealed a focus that fell between basic and applied research. The scientists there are not developing a specific product like a car, but because their research funding comes from the US Department of Defense they must show that their research will have practical military applications.

Our visits to both AFRL and Ford were similarly structured: they began with presentations that gave an overview of the organization and were followed by lab tours in which we interacted with the scientists working there.

One of the scientists at AFRL explained the structure of the research labs, which are broken into “directorates” by research focus, with each directorate located at different Air Force bases around the US.  We heard from scientists in the Materials and Manufacturing Directorate.

http://afciviliancareers.com/TeamAFRL/enterprise_locations.html

AFRL facilities and their respective directorates. Source: AFRL

After the introduction, we visited a ceramics lab where they research ways to strengthen materials like the ones used for space shuttle thermal protection tiles. When hot, the tiles become brittle and can be damaged by impact from debris.  We also toured a liquid crystal lab (think LCD TVs or smart phone screens) and tried on a pair of glasses that block sunlight with the flip of a switch.

http://commons.wikimedia.org/wiki/File:STS-118_damaged_tile.jpg

Thermal protection tile from the Space Shuttle Endeavor that was damaged by a piece of foam during launch.  Source: Wikipedia

At Ford, we saw a presentation from one of the managers who discussed the philosophy of the corporation, its current place in the economy, where the R&D department fell within the larger company, and some of the project goals for the department. We also heard from several scientists, including an OSU Physics graduate who had worked for Megan’s current adviser, about what physicists – as opposed to engineers or biologists – can do at Ford.

http://blog.ford.ca/2013/03/13/creating-the-future-at-fords-research-and-innovation-center/

Main entrance to Ford’s Research and Innovation Center in Dearborn, Michigan.  Source: Ford

Like our visit to AFRL, we next visited several labs and talked briefly with the scientists there. We saw what their workspaces are like, heard about their projects and got a glimpse of how they are carried out, and asked lots of questions about what their jobs are like. Anne’s favorite was the biological fuel scientist who was talking so enthusiastically about his project that our tour guide had to cut him off. Megan’s favorite lab uses alternative materials like corn, soy, and shredded money to replace some of the current plastics in car interiors. In the following video, you can watch a  presentation on soy-based car seats.

At Ford we also had the opportunity to eat lunch in their cafeteria and ask a few of the scientists who worked there in-depth questions about whatever we pleased. Many of them shared their experiences working in different departments and talked about the history of Ford.  It was interesting to hear how Ford once focused on more basic research and how that has changed recently, especially after the 2007 recession.

We both really enjoyed our visit to AFRL and Ford. It was very helpful to explore career options and talk to the people actually doing those jobs.  We now have a better sense of what industry and national laboratory jobs would be like and made some connections that may be useful in our job searches. Megan still has not decided exactly what path to pursue, but feels like she might want to work in industry after visiting Ford. While she does not want to work at either Ford or AFRL, these visits helped Anne cement her desire to work for a private company or applied-research government lab. We are both grateful for the opportunities to explore our career options, and encourage you to take advantage of similar opportunities to visit workplaces related to jobs that may interest you.

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About Anne Benjamin and Megan Harberts

picture for bioMegan (left) and Anne (right) are both physics graduate students doing experimental condensed matter research as part of the Center for Emergent Materials (CEM).  Anne and Megan have both previously written for A Day in the Life: So Why Physics?, What is Clean?, and Women in Science AND Sports.  You can follow Megan on Twitter: @meganharberts.

Physics Works Best if International

by Helena Reichlova

“Do you like to travel?” I have not met many young people who would answer “no” to that question. A much more interesting question is, “Why do you travel?” Although responses may vary, I might predict that they commonly contain words like “new” and “different.”   I imagine that’s because we like to interact with unfamiliar places, cultures, food, and people… simply because those interactions can be very refreshing and inspiring.

Conversely – when we travel – what is not different?  Almost anywhere in the world, with the exception of just two countries, you can buy a well known sweet drink called Coca-Cola.  But there much more common – often fancily called “global challenges.”  Although the interpretation of some of the global challenges depends upon your location on the planet, other interpretations are common for everybody.  Science, particularly physics, is for sure a universal source of such challenges.

But that is also one of the really cool things about physics.  In physics we have the freedom to travel everywhere and the problems that we are trying to solve at home remain the same.   In other words, the laws of physics don’t vary by location.  The only thing that might change (and most likely will) is how scientists approach the problems.  As a physicist who has experienced different cultures, I would like to share with you my experiences from several different countries and show that  international collaborations of scientists can, and do, achieve the best results.

My first experience with math and physics was in the Czech Republic, which is where I am from and where I did my bachelor’s degree in Physics. The classes that I took at Charles University were difficult, covering a lot of math formalism, and early on I felt like I knew more math than my colleagues from “real” math.  Some professors simply threw us into the middle of recent scientific problems; as a result we either sank (= approximately one third of the students did not finish their degree) or swam (=hours of studying at home were required to understand what he spoke about in class).

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One of the buildings in the Department of Mathematics and Physics in Prague where we had lectures (left) and graduation ceremonies (that’s me on the right!) at Charles University. We had to promise to uphold the good reputation of the university.

To add some variety to my education, I decided to go to Strasbourg, France, to study for my master’s degree.  It was there that I experienced for the first time a different approach to physics. Compared to my fellow French students, I probably knew (or had at least heard of 🙂 ) more equations. But in Prague we were not taught to work in teams, or, more importantly, how to present our results. In Strasbourg, however, one entire class was dedicated to working in small teams to understand and present a recently published scientific paper that our professor had selected for us. Working in the lab, I also saw a new approach to physics. The official policy did not allow students to work past 7 pm, after which the building was locked and an alarm system was activated. If you combine this policy with generously long lunch times (in the best dining halls that I have ever seen), nice sunny afternoons on the cafeteria terrace, and at least five weeks of holidays, one would guess that the stereotypical “French laziness” was exactly correct. But I don’t think that’s true, and the experts would agree 🙂 ; instead they are just more efficient. They organize their time wisely and are taught to be independent, having productive discussions with colleagues during long lunches or coffee breaks. And they are not exhausted from long nights spent working in the lab.

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Relaxed life in Strasbourg – a perfect network of bike routes, small cars, delicious food, and a beautiful historic city.

After one year in France, I went back to the Czech Republic and continued to work on another project toward my master’s degree. One way that I would describe experimental work in a Czech lab is that it’s like a hobby. I mean that I have the feeling that people working in science there usually love their work. It’s for sure not the best paid job, nor the most prestigious one (as being viewed as a ‘nerd’ by others doesn’t make people proud), but people work very hard and I am sure that they would oppose any policy that forced them to go home at 7 pm. The word hobby also reflects a homey atmosphere. Our “research center” looks more like someone’s house than an academic building and it is not long before you get a sense that everyone there knows everyone else.

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Homey atmosphere of the Physics Research Building of the Czech Academy of Science in Prague where I am studying for my PhD.

It follows naturally that my PhD work is an international collaboration as well – my advisors are Czech, Catalan (Spanish), and American. This variety brings positive differences. My Czech supervisor has taught me a kind of flexibility and has also showed me that being modest can work in science. On the other hand, I have learnt from my Catalan advisor that science does not need to be formal at all. As he says, science is just like an expensive version of Facebook – having a lot of friends (collaborations) who eventually like (cite) your status updates (scientific publications). A fellowship called the Fulbright has brought me to Ohio. In Ohio I have seen that people work really hard and the environment of a big university made me feel science is here very serious (compared to the hobby-like atmosphere that I described in Prague). I took only one class at Ohio State and I liked that the professor was open and encouraged discussions instead of using the equations to say everything. What I really like here is that good presentation skills are equally as important as good results. And I am really impressed by the frequency of scientific meetings and talks here (compared to rare scheduled meetings in Prague). Apart from the science, I hope that this helps me learn to communicate my work often and to keep track of what others are doing as well.

I have tried to describe the differences in cultures, habits, and styles that I have seen in my scientific career. I believe that physics is one of the fields that can really profit from this variety. Let me mention at least one example from a project that I was involved with last year.  German colleagues prepared and characterized a specific sample. The precision that they achieved is unmatched, but to put their work in a broader context it was necessary to confirm their results by another method. Here the flexibility and speed of Prague scientists would be beneficial to the project, but first someone needs to make the connection between the two groups and create the story – the perfect job for my communicative Catalan advisor. One physics experiment approached from different perspectives. And I think the final product is perfect!

In sum, I hope that I have convinced you that different styles of work can bring together the best results.  So, if you decide to study physics one day, don’t forget to travel!

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About Helena Reichlova

helenaI was born in the Czech Republic (Czechoslovakia at the time) and completed my undergraduate studies in physics at Charles University in Prague, the capital. I completed my MS degree in quantum optics and optoelectronics (in both the Czech Republic and in Strasbourg, France) and now I am working toward my PhD in the field of spintronics (which involves improving the present state of the art of electronics by including electron spin effects). Thanks to a Fulbright Fellowship, I have spent one year at OSU as a visiting researcher.  As a good experimentalist I really like exploring new things, including nonscientific activities like painting, snowboarding, and traveling to different places around the world.

Ponytail Physics

by Amy Connolly

I kept my hair pretty long as a kid, and I wore it in one or two ponytails most of the time (when it wasn’t in braids).  I have thick, thick hair, straight as can be.  Any curls needed to be strong enough that they would hold up to the weight of my hair.   My mom, who wanted her little girl to wear big, full curls, especially for pictures, would either fill my hair with curlers at night before bed so that I would have springy curls by morning, or devote time before school to working a curling iron through my hair.

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Picture of me with curls in my hair.

My mom and I didn’t know about the competing effects of weight, elasticity, tension and “swelling pressure,” that together needed to reach the right balance in order for those curls to stay in place.  But a group of physicists in England has studied the interplay between these effects on bundles of hair, developed a mathematical theory that can predict the shape of a ponytail, and published these exciting results in a high-profile scientific journal.  Let’s look at that publication and see what we can learn about both ponytails and scientific papers!

The abstract of a paper is a short synopsis at the start where we hear about the most exciting parts of the paper.  We learn that they are going to reveal a “remarkably simple” equation describing the shape of a ponytail, and that they verified the validity of their equation with lab measurements.  That’s right, they carried out experiments on ponytails in a scientific laboratory.  Let’s read on.

Where does this study fit into the world’s body of knowledge on hair?  In the introduction, the authors provide us historical context, evoking Leonardo da Vinci (who opined on the best way to illustrate hair), as well as Brothers Grimm (authors of the storybook tale Repunzel).  Despite the influence of hair in both art and science throughout history, they argue, it is then surprising that the physics that determines the form taken by a ponytail remains an open question.   They tell us about a previous paper on a related topic: someone by the name of van Wyk studied the compressibility of wool way back in 1946.

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Repunzel, from the Brothers Grimm fairytale collection,would let down her hair for the enchantress below (picture from tootsiegrace.blogspot.com).

Next we learn all kinds of interesting facts about human hair.   The diameter of an individual hair can be anywhere from about 2/1000ths to 6/1000ths of an inch.  The “linear mass density” of human hair is about 6.5 grams/kilometer.  That means that a hair that is a half a mile long would only weigh as much as 5 paperclips.  From this, they find that the length over which gravity on earth should bend an individual hair is about 5 cm, or about 2 inches. (You can verify this by standing in front of a mirror, isolating a single hair and holding it sideways.  It will bend under the weight of gravity with a radius of curvature of about 2 inches.)  Therefore, 5 cm is a special length for human hair on earth, and they quote all ponytail lengths in this paper relative to this special length.  They name this ratio the “Repunzel number!”  Brilliant!  (Footnote:  Another storybook allusion in science:  in searches for earth-like planets, astronomers seek new worlds that exist in a “Goldilocks” region where the environment is not too hot, not too cold, but just right.)

Now that the authors have educated us in human hair properties, we know enough to tackle the rest of the paper.

Next the authors go through the steps to derive the “Ponytail Equation,” starting with a set of assumptions.   First, let’s imagine that in the middle of a thick ponytail, you could insert an imaginary bubble, and count how many hairs enter the bubble and how many leave the bubble.  If none of the hairs end inside the bubble, then the number entering and the number that leave should be the same.  This is analogous to the “continuity equation,” which is used in the study of the physics of liquids called “fluid dynamics,” and it is the first assumption in their ponytail derivation.  Next, the authors account for all of the energy in a ponytail bundle.  It includes the elastic energy, or springiness, of the hair, the gravitational potential energy, and a confinement energy, for example due to the hair being tied by a band.

In the next step of their derivation, they find the ponytail shape that makes the hair bundle contain the smallest amount of energy.  Any system wants to go to a state of least energy, for example when you put a ball at the top of a hill, it wants to roll down.

The ponytail equation is summarized nicely by the plot below.  There are four forces acting to balance a ponytail.  The horizontal axis tells you where you are along the length of a ponytail, with the hair restraint at s=2 cm.  The vertical scale tells you the strength of each force.  Near the hair restraint, the pressure due to the hair band is the same as the elastic force of the hair pushing back (the yellow and black curves are the same height).  For most of the ponytail length, however, the weight is the strongest competitor to the pressure.  The tension of the hair is small compared to the other forces (take a fallen hair and try and stretch it along its length – the tension force is what pulls back).

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Results from the ponytail publication, showing the different forces acting along the length of the ponytail (the horizontal axis). On the vertical axis is the strength of the force.

The ponytail equation must be able to describe the ponytail data if it is to be regarded as a good theory.   In the figure below, the authors show that their ponytail equation (solid blue line) does agree with measurements of ponytail thicknesses at different lengths (solid black lines).  The new equation describes the data much better than the one derived by the van Wyk character who studied sheep hair (dashed red line).

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The ponytail equation matches the experimental data!

Finally, the authors remind us that there is lots more work to be done on understanding hair.  Their work can be extended to study other hair and fur geometries.  Imagine the possibilities!  In addition, their theory can be used to understand hair motion.  They end with a tantalizing reference to a paper that investigates why a ponytail swings left and right while a runner bobs her head up and down.

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About Amy Connolly

amyI grew up in Cincinnati, Ohio and went to college at Purdue University in Indiana where I found out that I love physics.  Since then I have lived Indiana, California, Chicago and England.  Now I am back in Ohio where I have been a physics professor at OSU for nearly 3 years.  I work on experiments that use radio antennas in Antarctic Ice to search for particle arriving here from deep in space called neutrinos.  I am so fortunate that learning new things about the universe is my job.  I also enjoy growing vegetables, and being really silly with my 3 year old.

Imperceptibly Fast

by Andy Berger

If the width of a human hair is the smallest thing visible to the naked eye, what is the shortest amount of time that we can distinguish? The phrase “in the blink of an eye” suggests an answer.  And it’s a decent suggestion.  Go ahead and blink.  Back already?  That was fast.  The average length of a blink is 0.1 seconds.  Compared to some physical processes – as shown below – that is actually a really long time.

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TOP: Time interval for some fast events.
BOTTOM: Frequency of various waves, shown directly below the amount of time for 1 period of oscillation.

I’ve always enjoyed music, as I’m sure many of you do.  In fact, one of my favorite hobbies is to play the guitar.  There is a lot of physics behind the workings of a guitar, but one of the most fascinating aspects is the speed of sound-producing processes.  Consider the simple case of playing a middle C (for those guitar players out there – this is the first fret on the B-string of the guitar, or for piano players – the key in the exact middle of a standard keyboard).  When this note is played, the string vibrates 261 times per second (or 261 Hz).

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TOP: Middle C as played on guitar.
BOTTOM: Position of the blue dot versus time.

This plot shows the position of the blue dot on the string versus time.  Note that, because it’s vibrating at 261 Hz, it takes less than .004 seconds to vibrate back and forth once.  In the time it takes you to blink, the string has gone back and forth 25 times.  While it’s vibrating, the string pushes around air molecules.  Eventually, these air molecules bump into your eardrum causing it to vibrate just like the string, and voila – you hear a middle C.

Of course, music isn’t terribly interesting if you just hear a single note at a time.  Often a guitarist might be playing a chord with six different notes, while the singer and bassist are each holding a note, all during a symbol crash and bass drum thump.  The speakers that we use to listen to recorded music have to vibrate accordingly to imitate all these different sounds (see a vibrating speaker in action).

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Signal responsible for vibrating the left and right speaker cones at 56.5 seconds into Metallica’s “No Leaf Clover.”

This is the actual signal sent to the speakers 56.5 seconds into (my favorite song) Metallica’s “No Leaf Clover.”    I chose this part of the song, because not only are there two guitars, a bassist, and a drummer playing, but they are supported by an entire orchestra.  It’s amazing to me that two tiny earbuds can accurately replicate the sound of nearly 100 instruments.  Sports fans: the amount of time depicted in this graph – .01 seconds – is the margin by which Michael Phelps won the 100m butterfly (and 7th gold) at the 2008 Olympics.

Our eardrums are not the only aspect of biology that are capable of high speed dynamics.  In my first blog post, I discussed the nanoscale machinery of DNA.  This machinery isn’t just small – it also operates very quickly.  Check out this real-time animation: DNA Transcription.  The enzyme zipping along the DNA is reading and copying the genetic code at a rate of about 30 nucleotides per second.  Try to count to 30 in one second.  In the time it takes you to blink an eye, 3 nucleotides have been transcribed simultaneously throughout the nuclei of most of the cells in your body.  I wish I had seen visualizations like this while I was studying biology, chemistry, and physics in high school.  The static illustrations in a textbook just can’t compete.

As impressive as the machinery of our cells is, they move at a snail’s pace when compared with the information processing speed of our electronic devices.  We have all come to expect a lot of our computers and cell phones.  But let’s stop and consider what has to happen to open a saved picture.  A typical image is a couple of megabytes in size.  Your computer has to individually read each of those million bytes in order to reassemble the image from the 1s and 0s that currently encode it.  If it took “the blink of an eye” (0.1s) to read each bit, it would take more than a day to load a single image!  Forget watching a video.  Luckily, a computer can shuttle information around blazingly fast.  The bits are zipping by at billions of bytes per second – and so as far as we are concerned, an image opens instantly.  To draw an analogy, when a hard drive is reading the bits that encode an image, the bit sensor is like a “jet plane flying at [18,600 miles per hour] one meter above the ground recording each blade of grass.

Technology has enabled us to do a lot in the time that passes in the blink of an eye.  It took the invention of high speed photography (1 frame every .04 seconds) to prove that all four hooves of a galloping horse are simultaneously in the air, tucked underneath its body.  Prior to these photographs, artists would incorrectly depict the position of the legs of galloping horses.  Time simply moves too fast for human perception to accurately keep up.

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TOP: Painting of galloping horses from 1821.
BOTTOM: High-speed photograph from 1878.

Today, scientists use “cameras” ten trillion times faster – taking snapshots once every femtosecond (10-15 seconds) – and can actually monitor the progress of chemical reactions.  There are 10,000 times more femtoseconds in the blink of an eye than there are years in the age of the universe.  Take a moment to pause and appreciate how quickly everything is buzzing around us, shaping our world and how we interact with and experience it.

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About Andy Berger

Picture1I grew up in Mansfield, Ohio, received my undergraduate degree from Kenyon College in Gambier, Ohio, and am now finishing my fifth year of the physics PhD program at Ohio State.  I am a condensed matter experimentalist with a focus on scanning probe microscopy, magnetism, and graphene.  I never would’ve guessed that would be my “job description” when I was in high school.  Away from the lab, I enjoy staying active – mostly through swimming, running, cycling, and soccer.