By Natalie Keyes, Megan Harberts, Nancy Santagata, and Amy Connolly “I had gone to the week-long GRASP physics camp at OSU during middle school and learned a lot from it, so as soon as my mom got a notice about … Continue reading
by Patrick Poole
Research life can be a lot of things—brainstorming experimental ideas, fixing broken equipment, crunching through complex theories. Sometimes you lift your head out of a textbook and realize you’ve stumbled across the underlying physics behind some simple everyday phenomenon, but you wouldn’t have seen it without trudging through the equations. Since at the end of the day many of us are driven by a desire to understand the way the universe works and to share that with others, I’ve made a blog, Everyday Physics, to explain events you see every day through the fundamental physics at their foundation.
A common misconception about blood is that it looks blue when depleted of oxygen, explaining why lighter-skinned people see blue veins in their arms. Here I’ll talk about how deoxygenated blood isn’t blue at all, and that the real reason for the color shows off some interesting aspects of how light interacts with matter.
1. An object’s color comes from how its atoms and molecules interact with light
Unlike water waves, light waves are able to travel in the absence of a medium—they come from stars to our eyes through empty space just fine. Light waves can also travel through materials as well, which often has some noticeable effect on the wave. Specifically, light is composed of oscillating electric and magnetic fields, and these fields will interact with and respond to atoms they encounter.
2. Certain colors of light will be absorbed in certain materials, so you won’t see those colors when you look at the object
The details of exactly how light responds to a material reveal a lot of interesting physics. Visible light incident on a material tends to give its energy up to electrons, increasing their energy via a process known as excitation. Excited electrons will eventually give off this energy, and can do so in a number of different ways—fluorescence, as is seen in neon shirt coloring, is one phenomenon that stems from one sort of de-excitation, but that’s another post. Often de-excitation occurs simply by the re-emission of the same frequency light that initially interacted with the electron, or by that excited electron knocking into an adjacent atom and transferring the energy away as heat.
The structure of an atom governs which energies will tend to excite electrons, or in the case of light, which frequencies will be absorbed into exciting an electron. Regardless of how that energy eventually leaves the electron, that frequency (or color) of light will be missing from the spectrum of light that originally hit the object. In this way a banana looks yellow because its structure is absorbing all frequencies of visible light except for yellow.
3. Light can also scatter within a material, which can remove some colors from the spectrum you see
Another effect that prevents light from going further into a material is scattering, where light gets deviated from its original path because of something in the way.
The details of scattering lie at the heart of a lot of everyday physics—things like why the sky is blue, or why beer foam is white—but that’s another post. It turns out that the size of the scattering particle relative to the wavelength of the incoming light determines the nature of the scattering—just like a ping-pong ball thrown at a beach ball will recoil differently than if it’s thrown at a marble.
The little density changes in skin and fat tissue are such that blue light tends to be scattered more than red. This means blue light won’t reach as deep in your skin before it gets knocked off course. You can test this by holding a bright flashlight on one side of the thin skin between your thumb and fingers—it’s red-tinted because those red frequencies are the most able to make it all the way through your skin.
4. More blue than red light is lost within your skin, but your brain is watching the ratio of blue to red light
Let’s focus now on two areas of your arm: one area where there is a big vein underneath skin (the vein region) and an area right beside that with no vein (the no-vein region). Skin with less melanin will be lighter, which means most incoming light gets reflected—so it appears white. Now, the blood inside the (mostly translucent) vein instead mostly absorbs light of all frequencies, but reflects a little bit in the red area of the spectrum—that’s why blood looks red.
(By the way, it really is red regardless of oxygen content: oxygenated blood in arteries is cherry red, and de-oxygenated blood in veins is dark red, but neither is blue! The slight color difference here comes because the iron-oxygen bond in hemoglobin absorbs less red of the red frequencies than non-bonded iron will.)
Let’s recap what we know so far:
- Both red and blue light get partially absorbed on the way to the vein.
- More blue light gets scattered on its way down to the vein.
- Blue light gets absorbed more than red once it reaches the vein.
In fact, there is more red light than blue light seen from the vein region of skin and from the no-vein region. So then what makes the veins appear blue?
Your brain can be fooled sometimes when it observes colors and patterns—this is the basis for most optical illusions—and there is a similar thing going on here. Even though both regions of skin reflect more red light than blue light, the no-vein region reflects a greater ratio of red to blue light than the vein region. This is because less blue light made it down to the vein and is absorbed strongly there. Your brain interprets the vein area as a little bit bluer by comparison to the surrounding skin. The same thing happens when you look at the figure above: the blue rectangles are the same color everywhere, but look a bit darker on the right where they are more surrounded by the darker red instead of the lighter white.
It turns out this blue vein effect only happens for bigger blood vessels that are a certain depth under your skin. It’s easier to see veins than arteries because they are typically larger when they are near your skin surface, like in your wrists and forearms. If you happen to have a vessel with even less skin covering than this, it will appear its natural red—take for example the vessels in your eyes, or on your retina.
Bonus physics – Non-red blood
Human blood (and that of many other animals) uses the molecule hemoglobin, where oxygen is bound to iron atoms. It’s this iron content that gives blood its red color, which the presence of oxygen makes a bit brighter. Creatures that don’t use iron to bind oxygen can have different color blood. For example, copper is the main oxygen receptor in hemocyanin, which is present in the blood of lobsters, snails, and spiders—as a result, their blood looks blue. It’s copper carbonate that makes copper statues turn green (like the Statue of Liberty), so perhaps this is involved in the famously green blood of Vulcans.
About Patrick Poole
I grew up on farms in Valdosta, Georgia, and did my undergraduate work at the Georgia Institute of Technology. Currently I just defended my PhD, which focuses on creating star-like temperatures and pressures using the ultra-intense Scarlet laser here at OSU. In my spare time I write on my science blog, www.everyday-physics.com, and perfect my mean racquetball serve.
by Casey Berger
The summer after my first year as a physics major, I hadn’t considered a Research Experience for Undergraduates (REU), thinking that I needed more research experience before I would be accepted to a summer research program. I know now that was unnecessary. Since returning to school to study physics, I had felt like an outsider in physics. My background was in communications: I had majored in philosophy and film production the first time I went to college, and then I had worked for two years at a desk job in Hollywood. I didn’t disassemble radios in my spare time to see how they worked. I didn’t build websites or design phone apps for fun. All those stereotypically “science” and “tech” activities were relatively new to me, although the interest in the subject matter had been there from the start. So I assumed that any program I went to would expect me to be proficient in building and repairing electronics and working with code. The thing I had not realized was that REUs are designed to be learning experiences, taking students at whatever level they may be at and helping them build a variety of skills needed for research.
After spending a summer working in a lab on OSU’s campus, I decided I should try to branch out for my following summer, and I looked up summer research programs for undergraduates on the National Science Foundation (NSF) website, and applied to the ones that sounded the most interesting to me. I was admitted to the Computational Astronomy and Physics Research Experience for Undergraduates (CAP REU) at the University of North Carolina at Chapel Hill (UNC). I spent ten weeks at UNC, one of eleven physics majors from schools across the country participating in the REU.
The REU focused on computational projects in physics, writing code and utilizing computers to make advances on specific projects across a wide range of physics topics. Computing skills are extremely valuable to physics, allowing physicists to simulate situations that are too complex to solve by just writing down a few equations. I didn’t see myself as a very strong coder, and I was anxious that I would fall behind, but I was surprised to discover that many of the students in my group hadn’t done much research or coding before, and each specific project was tailored to the individual’s level. Coding was not something I had seen myself doing when I started my physics major: I assumed most of the work I did would be with pencil and paper, but after I took my required programming class, I was hooked! Along with our computational projects, the REU included weekly seminars by professors at UNC where we could learn valuable computing skills, and there was no previous experience required.
The eleven of us shared a classroom as our office, and we came in each weekday to work on our projects. Each of us was paired with a mentor – a professor who would be overseeing the project. I was working with Joaquín Drut, a theoretical physicist whose research applies computational methods to solve the “many-body” problem. When you have small particles interacting, they all exert an influence on each other. If you just have two particles, you can solve the problem with pen and paper and find out how they are interacting, but as you start to work with more and more particles, it becomes very difficult, and computational methods are necessary.
My project was to test code that implemented a new method for understand properties of interacting fermions in a potential trap. This is the kind of system that occurs when experimentalists cool certain kinds of particles (like electrons or certain kinds of atoms for example) to extremely low temperatures. This may not sound like a very practical setup, but it’s actually a very important system. The things we can learn from studying this system can tell us a lot about how quantum mechanics works with larger numbers of particles, like the number of particles in the nucleus of an atom, which is actually very difficult to do. This can help us make special materials like superconductors, or understand how to manage quantum information and build a much faster computer.
My code was able to show a number of important properties. For example, as the temperature got lower, we saw the energy approach a specific value, called the ground state. We also were able to make density profiles, which are graphs of the average position of the particles. You can see from these plots where the particles are most likely to be, which is helpful for a lot of other methods that previously just had to estimate or guess where the particles would be.
Outside of the work, the REU also builds relationships between future scientists. The eleven of us stayed in the on-campus student apartments that were provided, and there were group activities set up by the program, like an afternoon at a theme park and a Fourth of July barbecue. The other students and I also planned a lot of fun outings by ourselves, like hiking at Hanging Rock State Park and arranging a tour of the Triangle Universities Nuclear Laboratory (TUNL) particle collider at Duke University. Everyone was working on different projects often in different fields of physics, but we helped each other with our presentation skills and with coding questions. We all keep in touch through a Facebook group, and I am looking forward to seeing them at conferences and perhaps even collaborating on future projects.
We also got to give outreach talks at the Morehead Planetarium and Science Center. These talks were both challenging and fun: condensing our research into a 3-minute talk intended for a non-science audience is no easy task. Instead of focusing on the details that consumed my day to day work, I had to find the big picture. I talked about quantum computing and how it could revolutionize our world, and I explained that my research would help give us insight into important properties that we need to understand if we want to use this technology. The audience was mostly elementary school children and their parents, and we got some really great questions. But in the end, it was great to see people get excited about science and ask lots of questions!
In just ten weeks, I learned so much about what it is like to conduct research at a university. I discovered how it feels to encounter a problem for which there is no solution manual, and then I found out how rewarding it is to discover those solutions for myself. I learned how to manage my time on a project when my day was not structured around classes. I found, much to my relief, that I loved it! This is good news for me, since I want to become a research scientist, but even if I had learned the opposite, it would have still been a valuable experience. You have to try something at least once before you know if you will truly like it or not. I actually liked my project so much that I am continuing to work on it even now that I’m back at OSU. I would encourage anyone who wants to go into research to consider doing at least one REU. The experience was amazing, and I learned more in one summer of research than I have in any of my classes on campus. There is just no other experience like it.
About Casey Berger
Three years ago, I returned to my hometown of Columbus, Ohio, after a few years working in Los Angeles, California, to go back to school at The Ohio State University. An eternal student, I am pursuing my love of knowledge all the way to a PhD. I hope to use my experience in the media and my education in the sciences to bridge the gap between science and pop culture.
by Andrea Albert
After I earned my Ph.D. from The Ohio State University, I took 6 weeks off to play video games, learn how to drive a motorcycle, and pack up the apartment. The last week of June in 2013 my husband and I drove across most of the country to Los Altos, California.
I had accepted a “postdoc” position at SLAC National Accelerator Laboratory as a Research Associate. As stated in my offer letter, my job is “to be actively involved in the physics studies with the Fermi Gamma-ray Space Telescope.” No more classes, just research. While my job gives me the freedom to study whatever I want, not being told what to do or having a specific task list from a supervisor is daunting.
My first day was pretty typical: took some basic training, got a badge, gave human resources all my info so they could pay me, and started settling into my new office. In the first few weeks, I had some work left over from a project I started at Ohio State to keep me busy while I thought about what else I wanted to start researching. I knew I wanted to continue looking for dark matter signals hiding in the gamma rays produced in our Milky Way Galaxy. Even though I technically have a supervisor, he is there to give me advice, not tell me what to do. Unlike in graduate school, the professors and senior scientists are now my colleagues, not my superiors.
My advisers at Ohio State, Brian Winer and Richard Hughes, helped make this transition pretty easy. I remember when I started out as a first year graduate student, I was clueless and needed them to tell me what to do. I quickly started getting my own ideas of things to investigate. In my last year of graduate school, Brian would walk in on Monday mornings and ask me “What great things are you planning to do this week superstar?” I felt, and still feel, like their colleague in addition to their student.
As a postdoc, you are only employed for a few years (typically 2-3, but sometimes up to 5). You are expected to demonstrate your capability as an independent researcher. My typical day involves downloading some data, asking a question like “I wonder how variable Y changes as I increase variable X?”, making a plot, studying it and then getting a new understanding that leads to another question “hmm, if variable Y increases then I’d expect variable Z to decrease”, and so on until I’ve developed a complete new understanding that can be published in an academic paper. I also attend meetings with my colleagues working on similar projects where we show each other our plots and talk about what questions they raise that we can study next. Some of these meetings are with people just at SLAC, but others are phone meetings with colleagues from all over the world. Its a lot like crime shows like CSI; you find clues (plots), those lead to more questions and leads (follow up plots), you discuss your theories and conclusions with colleagues (meetings) and get new clues from them. Then once you have a strong enough conclusion you can make an arrest (write a paper).
I love research and plan to stay in academia. My goal is to become a professor at a research university, but those jobs are tough to get. There are simply not enough professor jobs for every interested qualified person. Landing a tenure-track job is a gamble for anyone, no matter how good you are. You have to apply for the right job, at the right place, at the right time and sometimes the stars just don’t align. I’ve had plenty of rejections to things like undergraduate summer research jobs or graduate schools, but if it’s something you are truly passionate about you have to keep trying!
As I look ahead, I realize there is still a lot I will learn as I transition to becoming a more senior postdoc and hopefully a professor. I have already taken on more leadership roles in my research projects. I just got tapped to be the new coordinator of the Dark Matter and New Physics group in the Fermi-LAT Collaboration (or the “Dark Queen” as my dad likes to say). Its my job to coordinate our group of ~50 dark matter hunters from all over the world (my co-coordinator is in Stockholm, Sweden). I organize and run our biweekly meetings, read and approve all paper drafts and conference talks from the group, and coordinate the internal peer review process within our group.
I put together a couple faculty applications this season. This kind of application is different from college and graduate school applications. Sure I needed reference letters, but they didn’t require a transcript and I had to outline my research and teaching plan for the next 5-10 years. I had to start thinking about what my vision would be as the leader of my own research group for the first time. Thinking about myself in this kind of a role just a little over a year after getting my Ph.D. was scary, but my fellow postdoc Regina Caputo (UC Santa Cruz) said “Its time to put on our big kid pants!” I’m already starting to feel a little bit like an adult (I say typing in my Rainbow Dash robe) since I’m no longer in school and have a job that pays a decent salary. Also, I have colleagues asking me for my opinion on the direction of our group at SLAC since I’m the Dark Queen and I actually have good input to give!
Taking on a lot of new responsibility without a road map is super scary, but I just dive in and do my best. Actually, not having a specific plan just means I can’t fail at that plan. In the words of Project Runway’s Tim Gunn, my plan is to “make it work”. I always say, when confronted with a mountain, don’t look up at the whole thing…that’s scary. Just take it one step at a time and take a moment to look back at how far you’ve come every once in awhile. I have brought along a safety rope, though, and have some backup plans in case academia doesn’t work out. As a physicist, you learn leadership, research, communication, and teamwork skills that definitely translate outside of academia. Hey, only 6.5% of physics majors are unemployed!
About Andrea Albert
I am a Research Associate at SLAC National Accelerator Laboratory. I study gamma rays produced through the most extreme, energetic processes in the Universe. I am hunting for a small gamma ray signal from dark matter interactions. In my spare time I enjoy Jazzercise, playing video games with my husband Dylan Zanow, traveling, and sharing my love of physics. Learn more about me at www.physics-andrea.com and follow me on Twitter @PhysicsAndrea.
by Khalida Hendricks
I was born in Los Alamos, NM, where everyone’s parents work at “the Lab” (Los Alamos National Laboratory) …or you lie and say they do to fit in. Every child from Los Alamos is expected to become a doctor, a lawyer, or a scientist, and in general this is what happens. These options were presented as the only respectable paths. Either I would grow up and become a doctor, lawyer, or scientist, or I was doomed to become a miserable failure.
I didn’t want to be a scientist. My high school physics teacher loved cars and related every lesson to cars. There was no better way to make me hate physics and science in general. If you had told my high school senior self that I would ultimately dream of getting a PhD in physics, she would have laughed at you.
As a senior I had no idea what to do with myself. Everything I had ever shown interest in was dismissed by well-meaning adults. Still, the first time the recruiter called I hung up on him. A Los Alamos kid joining the Army? Are you kidding? But the recruiter was persistent, and eventually he found the magic word: linguist. I’ve loved languages all my life, but adults told me that language majors have few, if any, career options. My recruiter argued otherwise – if I became a military linguist, I could travel the world using my language skills, while also serving my country. The more I thought about it, the better it sounded.
I scored well on the language aptitude test and was given a choice of four challenging languages: Arabic, Chinese, Korean, or Russian. As a New Mexican, I like deserts so I picked Arabic. This was before 9/11, so I had no idea that Arabic language skills would become a valuable commodity. I simply picked Arabic because I like deserts. Yes. Seriously.
Army Arabic school is 15 months long, but Arabic came easily for me so I had plenty of free time. I had the luxury of being an eighteen year old with a well-paying job living in Monterey, California. I sampled everything I could: skydiving, scuba diving, mountain climbing, dancing, acting, and anything else that I could find. I got an associate degree in Arabic. I took classes in random subjects simply because I knew nothing about them. I would walk down a random aisle at the library to find anything new and interesting, or just surf the internet following link after link.
That is how I stumbled upon a website called “The Particle Adventure.” It’s changed a lot since then, but it is still around! I was enthralled. Why hadn’t they taught about particles in high school? I was fascinated by leptons and quarks and force carriers and interactions. After resisting my hometown mold for 18 years, the great irony was that I suddenly wanted to become a particle physicist…except that I still had a contract with the Army.
My first assignment was to Germany. While there, I taught myself Albanian, the native language of Kosovo, so that I could deploy to Kosovo. I was assigned to a Human Intelligence Team and got to drive around Kosovo just talking to people, drinking coffee with them, going to weddings and parties. For some reason the Army then decided to send me to Korea, where I was stuck on a tiny post just south of the Demilitarized Zone. To make life a little less tedious, I tried out for the 2nd Infantry Division Tae Kwon Do Team, and I got to travel around Korea doing Tae Kwon Do demonstrations. My feature trick was running up my teammate’s chest, launching off of his crossed arms, doing a backflip, and breaking a board mid-flip before landing. I also did a choreographed fight where I beat up the three biggest guys with fancy Hollywood style moves. This was a crowd-pleaser.
After a year in Korea, I received a mysterious letter informing me that I met the requirements for an unspecified position in US Army Special Operations Command (USASOC). Next thing I knew, I was at Ft. Bragg, in North Carolina, engaged in a rigorous training program. The job was just too cool to pass up, so upon graduating from the program, I re-enlisted and spent four incredible years at USASOC. I had the chance to try all sorts of things, from ice-climbing and dog-sledding to offensive driving and survival school. My nickname was “Spock” because I was always lugging books along on these trips. I read about particle physics as much as I could, but I knew that I couldn’t understand the stuff I really wanted to know without a more formal physics education.
In 2006 I was invited to try out for the United States Army Parachute Team, aka the Golden Knights. This was another one-of-a-kind life experience, so I re-enlisted a third time, swearing that it would be my last. I spent two years doing parachute demonstrations all over the country, and one year competing in parachute accuracy.
In December of 2009 I left active duty and joined the Reserves, which allowed me to study physics full time at North Carolina State University without giving up my Army retirement. The Reserves proved difficult to juggle with school. I fielded calls from my commander between classes. I fought to schedule my two weeks of annual training between the regular school year and summer internships and spent a full weekend every month playing Army instead of studying or getting homework done. Hopefully it will pay off but it has not been easy.
I also still have a habit of jumping out of airplanes. Before leaving active duty I placed fifth in parachute accuracy at the US Parachute Association National Skydiving Championships, earning a spot on the United States Skydiving Team. I skipped the first three weeks of my sophomore year to travel to Nicsik, Montenegro, and compete at the 31st Fédération Aéronautique Internationale World Style and Accuracy Parachuting Championships. I didn’t get an individual medal, but my team earned second place. I never really got caught up that semester but I think the experience was worth it.
I managed to do some physics along the way, too! I did internships at Fermilab and Jefferson Lab, as well as some undergraduate research at NC State. I’ve tried computational and experimental particle physics, theoretical nuclear physics, and astrophysics. Given my history of casting a broad net, it is going to be really tough for me to settle down to just one topic for my PhD!!
But at least I have gotten this far. Like I said, if you had told me back in high school that this is where I would end up, I would have thought you were crazy. It has been a long, winding, and often difficult road, but it has been full of adventures that I will never regret.
About Khalida Hendricks
It’s hard to believe sometimes but I now have 12.5 years of active duty and 18 years of total Army service. I plan to continue with the Reserves at least until I hit 20 years so I can get a retirement out of it. I have three beagles and two cats and I like to compete with my dogs in events such as obedience, agility, Barn Hunt, and other dog sports, whenever possible. Also I still get to do occasional parachute demonstrations as a member of the All Veteran Parachute Team, which was founded by one of my Golden Knights friends. I am currently studying particle physics, quantum field theory, and astroparticle physics as a PhD student at The Ohio State University.
by Nancy Santagata
A New Year’s post has become a sort of unofficial custom here at a Day in the Life. Therefore, in keeping with tradition, Amy, Megan, Natalie, and I would like to wish you a Happy 2015! 2014 was a busy year for us outside of the blog, as you might be able to tell by the fluctuations in time between posts. :) Rest assured that is not an indication that we are slowing down. We still love working with our friends here at Ohio State (and beyond!) to share their fascinating stories with you. These included Brendan Mikula’s discussion of the science behind teaching science, Kate Grier’s observations of the night sky from atop Kitt Peak, and a look into the fun of smashing atoms together with Christopher Plumberg. With all of these great stories, imagine our surprise when we looked at the numbers and saw that our most popular post was written by the editorial board! We each sincerely enjoyed sharing our individual experiences with being the only woman in the room, and we’re so glad to see that our readers did as well. Collectively, all of these stories helped the blog accumulate over 11,000 visits in 2014. That’s equivalent to all of the visits from both 2012 and 2013 combined! We are humbled by those numbers, and we owe the biggest of thanks to each and every one of our readers.
And the map – we can’t forget about the map!
It’s really filling in. We’d like to take a second to personally thank the one person in each of the following countries that single-handedly put or kept their country on the map this year: Botswana, Mongolia, Cambodia, Cyprus, Swaziland, the Dominican Republic, Jamaica, Barbados, Cape Verde, Ecuador, Mozambique, Albania, Nicaragua, Guernsey, Estonia, Antigua and Barbuda, Luxembourg, Ethiopia, Georgia, and Maldives. Nothing makes us happier to know that we are reaching readers all over the globe!
Looking forward, we’ll be sharing some pretty unique stories with you this year. Keep an eye out for posts about jumping out of perfectly good airplanes, what life is like once you finally finish your PhD, attempting research for the first time and loving it, and why the veins in your arm appear blue. The editorial board is going to sneak a few stories in as well. This winter I spent a few weeks in Alaska photographing the aurora borealis (also known as the northern lights), and the experience was too amazing not to share. And Megan and Natalie are preparing a post describing the workshop that ultimately brought Natalie to the blog. We hope that these new stories are as well received as our last!
In closing, we’d love to hear from you! What was the coolest science story that you read in 2014, either here at A Day in the Life or elsewhere in the blogosphere? Are there any topics that you’d like to read more about in 2015? Leave us a comment here, on our Facebook page, or tweet us @AditLatOSU.
Once again, Happy New Year!
About Nancy Santagata
As a sneak peak to my upcoming post, here I am knee deep in snow while on a hike at Creamer’s Field State State Migratory Waterfoul Refuge in Fairbanks, Alaska. I have been told that this getup reminds people of the character Violet Beauregarde from the 1971 film Willy Wonka and the Charlie Factory. Hey, when it’s -20 deg F, all that I care about is staying warm. :)
by Natalie Keyes
As a student barely out of freshman year, I was very pleased but also somewhat surprised when I got an email from the staff of A Day in the Life, asking whether I would join their blog as a high school board member. I met Amy, Nancy, and Megan, the founders of this blog, at the ASPIRE physics workshop I attended at OSU last summer. Little had I imagined when I signed up for it that the program would open doors for me far beyond the fascinating two days I spent learning about neutrinos and radio waves! I guess I must have done something right at the workshop, because here I am, typing this introduction. I’m so excited to join A Day in the Life and help ensure that its content is accessible and interesting to the target audience, high school students like me.
I have yet to take a physics course in school at this point, but I have been a science kid for as long as I can remember. My interests have evolved gradually over the years from math to astronomy to my great twin loves, physics and computer science. Curiosity about these topics and most anything STEM has led me to do a great amount of self-directed learning, an odd result of which is the fact that I know more about relativity than basic mechanics. I enjoy spending time reading books on theoretical physics and coding in various languages. I am also excited to be the head of the Software group this year for the Columbus School for Girls FIRST Robotics team.
However, one of the most unique and interesting science experiences that I’m anticipating in the coming year is this opportunity to work on A Day in the Life. I am looking forward to expanding my knowledge of physics, from the basics to the coolest frontiers, and delighted to help share that knowledge with others through contributing to this incredible blog!
by Kara Mattioli
Almost a year ago my research advisor and I decided to start a project that I initially thought was an exciting, but difficult, task. We had been discussing a research project that I was about to start working on, and my to-do list initially looked something like this:
- Help grow a material called graphene
- Study the graphene using a technique called Raman spectroscopy
- Figure out a way to make hydrogen atoms bond to the graphene (this is called “hydrogenating” the graphene)
The goal of my project was to learn how to study graphene using Raman spectroscopy, and then to use what I had learned to find out whether my graphene hydrogenations would work. At first, I didn’t know how to do any of the things on my to-do list. But I also had no idea of what was in store for me: working with awesome people, discovering a new subject that would fascinate me, and realizing that I love doing research.
I didn’t accomplish step #1 by myself. Instead, I found myself working with several other undergraduate students to learn how to grow graphene by a process called chemical vapor deposition. Two important questions had to be addressed: first, what is graphene? And second, what is chemical vapor deposition?
Graphene is a single layer of carbon atoms – it is incredibly thin, so thin that scientists call it a two-dimensional material because it barely has any thickness to it! The carbon atoms are bonded together and form little hexagon shapes. Chemical vapor deposition is a process where you start with a metal, typically copper or nickel, place it in a furnace, and then flow hydrogen, methane, and nitrogen gases over the metal surface while the metal is being heated. With the right amounts of gases and with the metal in a certain temperature range, you can actually grow a layer of graphene on top of the metal! It is a very cool process.
The group of students that I was a part of was called the Graphene Factory, which is a research group formed in the Physics Department at The Ohio State University to give students an opportunity to create graphene for other researchers to study. We first made graphene on copper, but it’s hard to study graphene when it is on copper because the chemical properties of copper sometimes obscure the properties of the graphene. So we transferred the graphene onto silicon dioxide. Each student in the group had a different specialty, and mine was Raman spectroscopy. So to complete step #2 on my to-do list, I had to learn about Raman and what it actually measures.
There are many different types of spectroscopy – it is the study of light emitted from or absorbed by atoms and molecules. For Raman spectroscopy, you shine light from a laser at whatever material you want to study, and you study the light reflected from the sample. Light from a laser is at one wavelength and one frequency, but materials can reflect light at many different frequencies. Atoms in a material will absorb light at specific energies and then re-emit some of the energy. A detector collects the re-emitted light and a computer plots the intensity of light emitted at each frequency, creating a plot called a spectrum.
Raman spectroscopy measures the difference in frequency between the frequency of the laser light and the frequency of light emitted by the material. This difference is called the Raman shift.
I took Raman spectra on our graphene samples and learned what the spectra were telling me about our graphene. That’s right – spectra are not just a display of different peaks! You can get a lot of information from them, and that is one reason why I think spectra, and especially graphene Raman spectra, are so beautiful.
The presence of the two big peaks, and the fact that the peak on the right is larger than the peak on the left, tells me that the material is graphene. The coolest part is that the peaks appear due to the vibration of carbon atoms in graphene that are bonded together. The carbon atoms vibrate side to side as well as up and down.
The width of the peaks tells me something about how many layers of graphene I’m looking at, and the fact that I don’t see a third peak before the first one tells me that our graphene is not damaged. Sometimes if carbon atoms are missing or if other molecules are bonded to the graphene surface, the graphene can have many defects and be unusable. And those are just a few of the pieces of information I get from looking at a single spectrum!
I studied lots of graphene Raman spectra to learn as much about our graphene as I could. Then came step #3 – trying to hydrogenate graphene. To do this, I place a graphene sample in a vacuum chamber, then heat the graphene and expose it to hydrogen. I’m still fine-tuning the hydrogenation details, but I did get to build my own vacuum chamber for this project, which was really fun!
I take Raman spectra of the graphene before and after my hydrogenations to see if the “normal” Raman spectrum of graphene changed. Remember the extra peak I mentioned earlier that only shows up if the graphene is damaged? Well, when I try to hydrogenate graphene, I want that peak to appear! It means that the graphene structure would be “damaged” because it would not consist of just carbon atoms anymore – a lot of the carbon atoms would be bonded to hydrogen.
I really enjoy interpreting spectra and finding out what does and doesn’t work in an experiment. In many ways, my job is kind of like constantly solving puzzles, and I love it. I like viewing research projects as puzzles to be solved, and with that view the things on my to-do list are more like putting a few of the pieces together. I’m so glad that I have the opportunity to learn how to become a scientist, and to discover new things that I never suspected I would love so much.
About Kara Mattioli
While I have always loved science, I never imagined that I would become a physicist. I initially came to Ohio State as a pre-medicine biochemistry major and had my heart set on becoming a surgeon. I decided that I wanted to learn more physics, so I changed my major to physics and ended up loving it. My career interests changed from medicine towards pursuing a full-time career as a scientist. I’m now entering my senior year as an undergraduate at Ohio State, and I plan on applying to physics graduate school. In my free time, I enjoy reading, hiking, and visiting art museums.
by Christopher Plumberg
Hi! My name is Christopher Plumberg, and I’m a sixth-year graduate student in nuclear physics at The Ohio State University, studying relativistic heavy-ion collisions. Those last four words may be a bit unfamiliar, so let me break it down:
“Relativistic” = wicked fast. Like, 99%-the-speed-of-light fast. Let’s just say, don’t get caught doing that on the freeway.
“Heavy ion” = large atomic nuclei. You might have heard that everything around us—water, air, kitty cats—is made up of atoms. And if you’ve ever thought about what atoms are made of, you might know they have a big part in the middle (the “nucleus”) and an outer part (the “electrons”), and the whole thing looks a little bit like honeybees buzzing around their hive. The “ion” part is basically just another name for the nucleus after its electrons have been stripped away, and the “heavy” part means we’re looking at relatively big nuclei (like gold and lead), rather than “light” nuclei (like hydrogen and helium).
“Collisions” = smashing things together. But you probably already knew that.
So there you have it. My job is taking large atomic nuclei, and smashing them together, wicked fast. Sounds pretty cool, right? Well, to tell you the truth, my job isn’t quite that glamorous. I don’t actually get to do the “smashing” myself: there are labs that do this for me, like the Relativistic Heavy Ion Collider (RHIC) in Brookhaven, NY, or CERN in Switzerland. My real job, however, is slightly different: I try to understand how these atom-crunching collisions actually work.
Of course, this is what physics really is: trying to figure out how things work. And knowing this helps us to understand why physicists went to all the trouble of smashing these atomic nuclei together in the first place. If you want to understand how a toaster works, one way to do it is to simply take the toaster apart (after it’s unplugged!) and peek inside. It turns out, if you want to understand how the atomic nucleus works, you just take it apart and look inside it!
The only catch is that, in the nuclear case, the object of study is way too small for a screwdriver to pry it apart, so we have to settle for smashing the nuclei together. How does that help? Well, the physical theories that we use to describe how the atomic nucleus works can also tell us what should happen when we smash two of those nuclei together at nearly the speed of light. If what we see in the laboratory matches what our theories predict, we know we’re probably on the right track.
Of course, this doesn’t happen automatically: there’s plenty of math that goes into making the connection between a physical theory (like the theory for an atomic nucleus) and the results of an experiment (like smashing two nuclei together). Working to make that connection between theory and experiment is a large part of the job of a theoretical physicist…in fact, that’s what my job is: I use the theories of nuclear physics to try to predict what experimental physicists (the folks who help run the atom-smashing machines) will measure in their laboratories. Working out exactly what those predictions are requires a good deal of intense math, but fortunately, we have computers to help us do most of it (phew!).
A friendly sidenote: you may be thinking about a career in science, but find the “math” part to be a bit scary at times. And that’s totally okay: most scientists are not math geniuses. In fact, I used to be somewhat terrified by really difficult math myself. The thing I have found is, if you tell yourself that the math will be too hard for you, then you will probably find it overwhelming. But, if you pretend instead that math is like a secret message—written in a coded language, to teach you something about the world that no one else has ever figured out before—then math becomes much more exciting, and it actually becomes a bit easier, too. Of course, like any code or language, math has rules, and it often takes some practice to get really good at using them. Nevertheless, if you are willing to do some hard work, chances are that you will surprise yourself with how much you are capable of doing. So keep at it.
The special focus of my research has to do with ‘taking pictures’ of heavy-ion collisions (via a technique known as “femtoscopy”). Here’s how it works: when two nuclei smash together, they are actually travelling so fast that they crash right on through each other. In the process, some of their energy gets converted into new particles that fly away from the collision—particles that we can measure. These particles can fly away in any direction, but the rules of quantum mechanics tell us that these particles prefer to ‘clump’ together in a way that depends on how far apart they were when they were created. If we can measure the ‘clumpy-ness’ of the emitted particles, we can learn something about the size and shape of the collision.
And now comes the really cool part: using femtoscopy has allowed me to explain some puzzling triangular patterns that experimentalists have noticed in their data. Some folks thoughts that these patterns only showed up because the collisions themselves were triangular in shape. However, I was able to show that these “triangles” are actually due to the way that the collision itself expands, giving us some important clues about the behavior of an exotic form of matter—known as the quark-gluon plasma—which is formed during the collisions, and which is one of the hottest topics in nuclear physics today.
But there is still more work to be done, and the next big step might be made by a bright young scientist like you. Nuclear physics is still an active field of research with much to teach us about nature. So what will your contribution be?
About Christopher Plumberg
My name is Christopher Plumberg and I am a year or two from completing my PhD in nuclear physics at Ohio State. My undergraduate work was done at Eastern University in astronomy and astrophysics, in cooperation with Villanova University. When I’m not working on my research or learning something new about math or physics, I’m probably reading books on theology and philosophy of science, practicing the piano, or hanging out with my awesome fiancée, Allyson (who is pictured with me to the left).
by Rebecca Reesman
Upon beginning grad school people often have aspirations of being a professor at a university or being a researcher at a national lab. In the long run, less than half of physicists with PhDs will still be in academia, though many will be at national labs or working in industry. However, during my 3rd year of grad school I decided that physics research is not what I want to do long term.
After I complete my PhD, I plan to promote science and reasoning skills through a combination of policy development, education, and communication. My love for physics and mathematics has taught me a great deal about using data to make decisions. This is true whether it is about astrophysics or life. My dream is to help people understand and appreciate the world in which we live using science, data, and evidence-based reasoning. Being able to make sense of numbers, such as statistics, is important for thinking critically. Our country remains low in science education and high in innumeracy. Making learning and understanding science more accessible and desirable for the general public is a key component of my aspirations.
Consequently, I have been looking into many of the fellowships that are available for scientists to transition into policy. The big one is the AAAS Science & Technology Policy Fellowship. This fellowship takes PhD scientists and puts them in Washington DC to influence policy. There are two general tracks, the executive and the congressional track. The former offers you the chance to work in a national agency such as the National Science Foundation (NSF) or the Department of Energy (DOE), for example. The latter gives you the opportunity to work in a congressional office, assisting with science related issues. As a result I have decided I should familiarize myself with AAAS — which is the American Association for the Advancement of Science. AAAS is an international non-profit organization that, according to their website, seeks to “advance science, engineering, and innovation throughout the world for the benefit of all people.” AAAS is also the publisher of the prestigious journal Science. They are in the unique position of supporting all scientific fields whether it concerns policy issues, education, or enhancing communication between scientists, the public, and the government. A short video about the fellowship program is included below.
Back in February I was able to attend the AAAS Annual Meeting in Chicago, Illinois. I was even fortunate enough to win the Joshua E. Neimark Memorial Travel Assistance Award from AAAS to present a poster on my research at the conference. The research I presented dealt with looking at gamma rays, or high-energy photons, interacting with ambient light from stars. This allows one to understand the history of when stars formed. Through this interaction I can also look for new particles interacting with gamma rays as they travel to detectors on/near Earth.
Given the size and scope of the conference, and the fact that the poster sessions were open to the public, I got to talk about my research with a wide array of people. This included talking to a high school biology teacher, something that doesn’t get to happen at a physics conference. It was very cool to share my research with people of such diverse backgrounds; the range of attendees allowed me to practice explaining my research at a multitude of levels.
Prior to this meeting I had only attended conferences and workshops that pertained to my subfield, astroparticle physics, and the differences were substantial. Workshops typically consist of 30-50 graduate students and post-docs. Conferences focusing on a particular subfield are likely to have a couple hundred attendees and consist of many technical talks. However, the AAAS Annual Meeting consisted of thousands of people from a wide array of backgrounds. It was far and away the biggest and most exciting scientific meeting that I have ever been to! There were technical talks in all sorts of fields from mathematics to biology, talks discussing getting more women in STEM fields, talks about the math of elections, and talks about the science of science fiction. A talk titled “Where’s my flying car? Science, science fiction, and a changing vision of the future” included Lawrence Krauss, a well known astrophysicist.
There were many talks about science communication, and in fact the first day of the conference was dedicated entirely to science communication! Session titles included “Engaging with Journalists,” “Engaging with Social Media,” (see video below!) and “Engaging with Public Programs.” The speakers have impressive resumes, including Paula Apsell who is the Senior Executive Producer of NOVA and NOVA scienceNOW on PBS, Danielle Lee who writes the Urban Scientist blog on Scientific American, and Ben Lillie who is the Director of The Story Collider.
I was particularly excited to see Danielle Lee there, as I have heard about her efforts of getting underrepresented minorities in STEM fields. In fact I spoke with her, one-on-one, afterwards and discussed some ways to improve the Society For Women in Physics group at OSU! She suggested we get in contact with STEM minority groups already established on campus, such as the National Society of Black Engineers (NSBE), and get involved with their activities. Here’s a link to watch all of the talks about science communication.
One evening I attended a mixer for past/current/future AAAS Science & Technology Policy fellows. This was an amazing opportunity that allowed me to learn about the exciting projects that fellows get to do. I made many connections through this event — this included meeting an alum of the Ohio State Physics Department, Gregory Mack, who is a current fellow working at the National Science Foundation. Greg gets to work on STEM outreach initiatives such as finding ways to convey new scientific findings to the public.
This conference got me excited for my future. I got to learn about more ways I can get involved in both science policy and science communication. I learned about companies that focus on bringing together scientists, policy-makers, and other stakeholders to facilitate dialogue on science-related policy issues. For example, a company called COMPASS holds workshops and training sessions for groups of scientists to develop these skills. Based on my experience attending this conference, I am excited about one day applying to the AAAS fellowship program, but I also learned about other opportunities to pursue a career that embraces science policy and science communication.
About Rebecca Reesman
My name is Becca Reesman and I am wrapping up my PhD in Physics at Ohio State! In 2009 I received my undergraduate degree from Carnegie Mellon University where I double majored in physics and statistics. I have a horse (Dandy) who has moved with me throughout my collegiate career; being able to ride on a regular basis has been an important part of my life.