“Do boys like you because you are smart?”

In 2011, I was a first year physics PhD student and new executive board member of the Society of Women in Physics (SWIP) at the University of Michigan. While I had been a member of a women in physics group as an undergraduate, I had never done public science outreach. SWIP at UM, however, had a strong history of public outreach, which I was very excited about. In addition to yearly outreach events to 8th graders and high-school students, our president at the time wanted to expand our outreach efforts to a slightly younger audience and bring two local Girl Scout troops, 4th-6th graders, to campus.

I helped organize and volunteered for this outreach event, where we brought over 30 girl scouts to campus and treated them to a day of fun, interactive physics demonstrations and liquid nitrogen ice cream. Since outreach to girls this age was new to us as a group, we asked the troop leaders to compile a list of questions that the girls wanted us to answer. This way we’d get an idea of what they wanted to learn about besides the physics of the demos we’d be presenting and could answer the questions to fill up downtime during the day when it came up. Here is the entire, unabridged, list of questions we received.

  • What is (are) your name(s)?
  • Do you like the U of M campus?
  • Do you play sports for U of M?
  • Do you like apple or pumpkin pie?
  • Do you like hot dogs or bratwurst better?
  • What exactly is physics?
  • Do you like being a physicist?
  • Is it hard to be a physicist?
  • Is it a lot of work?
  • What does it take to be a physicist?
  • Do you have to go to college to become a physicist?
  • What other schools can you go to to become a physicist?
  • How much does school cost?
  • Are there scholarships for physicists?
  • Do you have to get good grades to become a physicist?
  • How long have you been a physicist?
  • Why did you choose to study physics?
  • What made you want to be a physicist?
  • Did someone make you be a physicist?
  • Was there someone in your life that encouraged you to study physics?
  • Did you want to be a physicist when you were little?
  • What did you study when you were our age that got you ready to study physics in college?
  • Do boys like you because you are smart?
  • How did you KNOW you wanted to be a physicist?
  • What do you like most about studying physics?
  • Are there lots of cool girls studying physics?
  • What percentage of women are physicists?
  • Are your family members physicists?
  • Are you married to a physicist?
  • What kind of things do you do as a physicist?
  • Do you get to do a lot of experiments?
  • Is your job dangerous?
  • What things do you put in liquid nitrogen?
  • Have you ever hurt yourself with the liquid nitrogen?
  • Have you ever done experiments on moldy cheese?
  • What jobs do you get after you study physics?
  • Do you teach?
  • Do you work for a company?
  • Do you like your choice in jobs?
  • What is the coolest physicist job?
  • How much money does a physicist make?

While some of the questions are very straightforward (“What is (are) your name(s)?”) or downright silly (“Do you like hot dogs or bratwurst better?”), a few trends become immediately clear.

  1. As we expected, the girls did not seem to have much of an idea about what a physicist is or does (which is a significant motivator for doing outreach the first place).
  2. The girls were surprisingly curious about issues of money, with questions such as
    • How much money does a physicist make?
    • How much does school cost?
    • Are there scholarships for physicists?
  3. There seemed to be some concern about how difficult (and possibly unpleasant) being a physicist would be.
    • Is it hard to be a physicist?
    • Is it a lot of work?
    • What does it take to be a physicist?
    • Did someone make you be a physicist?
    • Do you have to get good grades to become a physicist?
  4. Finally, and perhaps most surprising to us, several of the questions centered on gender.
    • Are there lots of cool girls studying physics?
    • What percentage of women are physicists?
    • Do boys like you because you are smart?

As physicists, we were (and are) astutely aware of the gender disparity in our field, and this was already our prime motivation for starting an outreach project explicitly aimed at girls. We know that positive female role models in science are important to attract more women to the field. But we didn’t know that this type of gender inequality was already plainly evident to 8-11 year old girls.

The question “Do boys like you because you are smart?” was the most painful for us to see. It implies this young girl may have the impression (or the experience) that the opposite is true. It’s troubling that whether a boy will like her is such an important issue for a young girl at all, as if we as a society are already conditioning her to define her worth by her romantic appeal. But it’s even more troubling that being smart is seen as a barrier to this. The question about marriage may also fall into this category. “ Are you married to a physicist?” was an unexpected question for us. Did this girl scout just happen to know a couple of married physicists? The troops were from Ann Arbor, which is a university town, so it’s possible. But it may mean something else—that from the perspective of a 10 year old girl, in order for a woman studying physics to find a man who might like her romantically, that man might have to be a physicist also.

There’s been a lot of discussion about sexism in academic science after this article in the New York Times op-ed came out a couple of weeks ago entitled, “Academic Science Isn’t Sexist.” The authors discussed their own study which investigated hiring and promoting practices for male vs. female faculty. There have been several rebuttals, but I’m not going to discuss this in detail here. The point I want to make is that it doesn’t matter. If elementary and middle school girls are still asking, “Do boys like you because you are smart?” then we have much bigger problems than whether junior faculty in the academic sciences are promoted at the same rate.

Imaging the Universe with Gravity: Gravitational Lensing

You may be familiar with how lenses bend light to create images, such as the biconvex lens shown below. The lens is made of a material such as glass or plastic that is denser than air, so light will bend at the interface between the air and the lens.

Large_convex_lens

But did you know that any massive object can be used as a lens? As Einstein’s general relativity tells us, gravity can be seen as massive objects bending spacetime. If you imagine the Earth as a bowling ball on a trampoline, the weight of the bowling ball pulls down the fabric of the trampoline, just as the mass of the Earth bends the spacetime around it.

Spacetime_curvature


In a phenomenon called gravitational lensing, large massive objects such as galaxy clusters bend light from distant sources, creating distorted images that we can see here on Earth. The diagram below from the European Southern Observatory (home of the creatively-named European Extremely Large Telescope) shows how this works. The foreground galaxy is massive enough that it bends the light from the background galaxy around it, much like an ordinary lens does. The telescopes on Earth see a distorted image of the background galaxy that contains multiple images, often in an arc around the foreground galaxy. An image below from the Hubble Telescope has several examples of gravitational lensing. There are three distorted images of a lensed galaxy and five of a lensed quasar.

Image: NASA/ESA, K Sharon (Tel Aviv University), E. Ofek (Caltech) https://hubblesite.org/newscenter/archive/releases/2006/23/image/b/

Image: NASA/ESA, K Sharon (Tel Aviv University), E. Ofek (Caltech) https://hubblesite.org/newscenter/archive/releases/2006/23/image/b/

Besides being really neat, this technique is especially useful for detecting dark matter. Since dark matter doesn’t interact with light, it can’t be seen directly. However, since dark matter is very massive, it can be detected indirectly by the distorted images it creates of normal matter through gravitational lensing. Experiments like the Large Synoptic Survey Telescope aim to take advantage of gravitational lensing to map the dark matter in the universe and provide clues to its nature. For a bit of added intrigue, it turns out that mass-energy equivalence (what E=mc2 is all about) means that energy can bend light just as mass can—so in addition to providing information about dark matter, gravitational lensing can also be used to study dark energy! The effect is much smaller, so it’s called weak gravitational lensing, but experiments such as the Dark Energy Survey are using gravitational lensing to study dark energy in much the same way as it can be used to study dark matter.

Physics Graduate Student Research at the University of Michigan

I recently gave part of a weekly public lecture called Saturday Morning Physics at the University of Michigan, where I’m currently a Ph.D. student. These talks are normally given by professors, but this time it was shared by three Physics Ph.D. students, all National Science Foundation Graduate Student Research Fellows. We each took 20-25min to describe our research for a general audience.

I’ve included our bios and more detailed summaries of our talks below. Each of us spoke for 20-25 min if you would like to skip ahead for a particular talk, but I recommend watching the whole thing!

*Note: For some reason, the settings on YouTube make the video start around 25 minutes, which is already in the middle of my talk. Next to each of our names below, I’ve listed the time our talk starts so you can skip around easier.

Benjamin Lawson
Ben

Starts at 00:25

Topic:

Materials can be categorized and described in many different ways – a familiar example is whether they are conductors (can carry electricity) or insulators (cannot carry electricity). Ben will discuss the search for novel materials that do not fit into either of these categories and talk about the properties of some completely new types of matter.

Bio (beware the puns):

Ben received his Bachelors of Science in Physics from the University of Texas at Austin in 2012. In his first two years at Texas, Ben worked on neutrino experiments at Fermi National Accelerator Laboratory with Professor Sacha Kopp. His work there had a changing flavor of programming and hardware, but he decided that there was no reason to charge forward in neutrino experiments and leapt on from particle physics that, though was charming, was also a little strange. For his last two years of undergrad, he did laser scattering experiments on hydrogen and methane with Professor Greg Sitz. He got very stoked about this work and, when he shed light on new properties, his whole group would get excited. Ben is now in the Ph.D. program at the University of Michigan and is doing work in Condensed Matter Physics with Professor Lu Li. Though his future is not crystal clear, his new group has velocity. Ben spends most of his time taking data, but he periodically must bloch out time to band together with his colleagues and chern out actual numbers to publish. As far as Ben is concerned, Lu Li’s lab is the coolest place at the University of Michigan.

Jenna Walrath


jenna

Starts at 23:02

Topic: 

Thermoelectric materials directly convert heat to electricity without any moving parts, offering a way to reliably recover waste heat in systems ranging from power plants to cars. Jenna will explain thermoelectric generators and describe her work studying thermoelectric materials on a nanometer scale with the goal of better understanding methods for increasing efficiency.

Bio: 

Jenna received her Bachelors of Science in Physics from Purdue University in 2011, graduating Phi Beta Kappa. During her time at Purdue, she worked in particle physics for Professor Daniela Bortoletto on both the CDF experiment at the Fermi National Accelerator Laboratory and CMS at the Large Hadron Collider. Taking advantage of the NSF Research Experience for Undergraduates, she also spent two summers working in gravitational wave physics, building optical motion detectors for the LISA project at the University of Washington and then for LIGO at Caltech. Jenna is now a third year Ph.D. student at the University of Michigan working with Professor Rachel Goldman in condensed matter physics, studying nanostructured thermoelectric materials.

Timothy Olson

tim

Starts at 43:40

Topic: 

The fundamental forces and laws of physics can be thought of as arising from special symmetries of nature. Tim will present a new way of describing some of those symmetries geometrically using volumes of higher-dimensional shapes.

Bio:

Tim graduated from Valparaiso University summa cum laude in 2011 with a Bachelors of Science degree in Physics and Mathematics. While a student at Valpo, Tim’s research covered many aspects of fundamental physics. He spent one year designing and testing components of an experiment to measure the neutron electric dipole moment at the National Institute of Standards and Technology in Maryland.  Tim was also involved in two high-energy collider experiments. The first was with the STAR collaboration at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. Then in 2010, Tim traveled to CERN where he developed software used by the ATLAS experiment to monitor detector systems in the Large Hadron Collider. He is now a third year Ph.D. student working with Professor Henriette Elvang at the University of Michigan. Tim is actively engaged in theoretical particle physics research on aspects of gauge theories, renormalization group flows, and scattering amplitudes.

Ben, Tim, and Jenna are currently supported by the National Science Foundation (NSF) Graduate Research Fellowship Program. These highly competitive fellowships are awarded to graduate students in STEM fields and provide three years of research funding as well as access to additional NSF resources.

Don’t Blink: The Quantum Zeno Effect and the Weeping Angels

If you are a Doctor Who fan, you’re probably already familiar with the Weeping Angels; if you’re not, head to Netflix immediately and start with Season 1 of the 2005 reboot. This article will still be here when you emerge, bleary-eyed, a week later after the ensuing binge. Trust me; it’s worth it.

For the still uninitiated, however, the Weeping Angels are a race of aliens in the Doctor Who universe that are described as “quantum-locked.” When you are looking at them, they appear as stone angels, the kind you might see often around gothic architecture. The second you look away, however, they are free to move, able to exist in their natural state. Upon contact, they can either snap your neck, killing you instantly, or send you back into the past, feeding on the “potential energy” of the life in the present you could have lived.

Doctor Who Weeping Angel from The Time of Angels.JPG

While Doctor Who, like most other SciFi serials, often spouts random scientific-sounding words to explain convenient plot devices (“reverse the polarity!”), the Weeping Angels are actually based on a fascinating phenomenon called the Quantum Zeno Effect. (Warning: If you’re not comfortable with words like eigenvalue, the Wikipedia article linked to here is probably too technical.)

Before I go any further, I want to give another important warning. Whenever anyone without a degree in Physics, Chemistry, or a related field of engineering uses the word “quantum,” it’s safest to not believe anything they say next, as it’s likely complete malarkey. I currently have two degrees in Physics, and you should still be highly skeptical that I will succeed in being 100% accurate in what I’m about to explain to you. Quantum mechanics is weird, and while I can write down a bunch of equations for you that will be 100% correct, I may lose something while translating the ideas into English. I’m going to use metaphors that probably aren’t 1:1 with the truth.

The fundamental reason for this is that our macroscopic world, the one you and I interact with every day, is nothing like the world ruled by quantum mechanics. Quantum particles behave both like particles and waves, which leads to some pretty strange things. For example, if you conduct an experiment where you drive your car off a cliff, you pretty much know how that’s going to end. But if you do the same sort of an experiment with an electron, there’s a good chance it will just bounce back, depending on the height of the cliff. Similarly, if you drive your car into a building, your car is never going to pass through unharmed. But electrons can tunnel through barriers, and any college junior who’s taken a quantum mechanics course can calculate the probably of it doing so just as easily as you can predict the probability of your car doing so.

ThelmaLouise4_001Pyxurz

P=0 means this is always a bad idea.

So in this mad quantum world, we get really cool things like the Quantum Zeno Effect, which lead to awesome SciFi monsters like the Weeping Angels. So what is the Quantum Zeno Effect? Basically, it says that a watched pot never boils, if the watched pot is a quantum system. If you keep measuring a quantum system is some state, that state will never be allowed to change. The name comes from Zeno’s Arrow Paradox, where if you watch an arrow in flight and look at any single instant in time, the arrow appears motionless. You can pick any point in its flight, and at that single point, it’s occupying a single point in space which is not changing. So how can the arrow be both in flight and stationary at the same time?

It’s well known that observing a quantum system changes the system. In the Quantum Zeno Effect, this is turned on its head a bit since the change induced by measurement is that we can keep the system from changing. Let’s look at an actual experiment. There have been a lot of experimental verifications, but I like the 1990 paper by Nobel laureate David Wineland because I suspect the secret to his genius is in his mustache.

David Wineland 2008.jpgHe took a collection of laser-cooled Be+ ions, excited them to a higher state by applying a radio pulse, and measured which state they were in using scattering from a high frequency pulse. He found that he was able to prevent the ions from being kicked to the higher state just by observing which state they were in. Now, that explanation might sound a little dense, and the details are complicated. So, I’m going to try to explain the idea in a distinctly non-scientific way.

Say you are trying to kick a ball up onto a table. The ground is the lower energy state, and the table is the higher energy state, because up there it’s subject to the pull of gravity. If you kick the ball with the right amount of force, giving it the proper amount of energy, you should always be able to get it up onto the table. But then, your friend comes by and looks at the ball, and despite the fact that you’re still kicking with the same force, the ball just won’t get up and stay on the table.

That clearly makes no sense whatsoever, but at the quantum level, that’s essentially what happens. Bringing this back to the Weeping Angels, that means that when unobserved, they exist in a state that is free to move and evolve, which in this case potentially involves time murder. However, if they are continuously observed, they can never move. But the moment you blink- well, you can blame quantum mechanics for what happens next.

You are the 5%: The Mystery of the Missing Universe (Part II)

In my last post I left off with the revelation that scientists have no idea what makes up 69% of the universe. This is what we call Dark Energy. As I explained before, the name is kind of misleading—dark energy isn’t directly related to dark matter in any way that we know of. It’s just called “Dark” because we have no idea what’s there. The pie chart of the universe might as well look like this:

Here be dragons

If we have no idea what it is, how do we know it’s even there?

The short answer is that the universe is expanding, and this expansion is accelerating; everything is getting further and further apart at a faster and faster rate. Something has to be causing that expansion, and that cause is named Dark Energy.

First of all, how do we know the universe is expanding?

If the universe wasn’t expanding, when you look out from Earth at other galaxies, you would expect some of them to be moving toward us and some to be moving away from us. However, in 1929 when Edwin Hubble measured these velocities, he found that ALL the galaxies were moving away from us! Additionally, the further away the galaxies were, the faster they were moving away from us.

This was pretty surprising at the time, but then things got even weirder when in 1998, the Hubble Space Telescope (of course named for Edwin Hubble), looked really deep into space and found that this rate of expansion was slower in the early universe. To get a physical picture of what this means, NASA has a nice graphic below, where the shallower the curve, the faster the rate of expansion. The universe expanded rapidly right after the big bang, but this subsided and a slower expansion took place for several billion years. Then, this expansion started accelerating about 7.5 billion years ago. This discovery won astronomers Saul Perlmutter, Brian Schmidt, and Adam Riess the Nobel Prize in Physics for 2011.

 

What does this mean? Am I getting bigger, too? Is the universe going to rip apart?

If the whole universe is expanding at an accelerating rate, it seems logical to assume that the distance between all of the atoms in the universe is getting larger. However, this isn’t quite the case. The atoms in our bodies have other forces holding them together that are stronger than whatever is pushing the universe apart. So, our own galaxy isn’t expanding because everything in it is bound together- by gravity, electromagnetism, and by the strong force. What’s happening is that the distance between things- between galaxies- is expanding.

A good model to think about this is the raisin bread model of expansion. When you bake raisin bread, the bread rises and expands, meaning the distance between all the raisins is increasing- but the raisins themselves don’t get any bigger. In the same way, it’s space itself that’s expanding, not the things inhabiting it. This is only true for now, however; unless this expansion starts slowing down, eventually all atoms will start to get farther apart too.

As to what this means about the fate of the universe, no one has a clear picture of what will happen. One possibility is that everything will expand to the point where atoms are pulled apart from each other, resulting in a “Big Rip.” Another, possibility is something called the heat death of the universe. As galaxies continue to get further and further apart from each other, the universe could eventually reach a constant temperature- meaning that no more heat could move from one place to another. Stars would no longer be able to shine shine and the entire universe would essentially become a cold, dark void.

But you and I will be dead by then anyway.

What could it be?

This is one of the biggest questions in Physics currently. We know what it does- causes space to expand- but we don’t know how, which makes it difficult to tell what it is. Some hints can be found in Einstein’s equations of gravity, where a number called the cosmological constant appears.

This number describes the energy density of the vacuum of space. This is sort of a strange concept; it means that “empty space” just doesn’t exist—there’s no such thing as “nothing”. The value of the cosmological constant determines whether the universe is shrinking, static, or expanding. To match the observations of dark energy, it has to be positive, generating negative pressure which counteracts gravity on a cosmic scale.

However, no one has found an explanation for exactly what this constant means. The positive pressure terms are caused by the force of gravity, which we can explain (for the most part) with equations that match observations. But the negative pressure term has no known force associated with it, so we just call it Dark Energy. So, this leads to one of the ideas of what Dark Energy could be- the fifth fundamental force.

Another possibility tries to directly explain why the vacuum of space itself has energy. In quantum mechanics, virtual particles can pop up and disappear instantaneously in the fabric of space. However, calculations using this theory don’t match the observed strength of Dark Energy, so something’s still not right there.

The last explanation that I know of (and the one which I think is the least likely) is that Einstein’s equations are wrong, and gravity is even weirder than we already know it is. There are some theories that suggest you could modify the equations of gravity to still match the observations we know of, but also explain the expansion of the universe. None of them have quite succeeded, but it’s still an avenue of exploration.

What we need are more experiments to probe the properties of Dark Energy. The base level of what is known is much less than with Dark Matter, so this is a pretty big challenge, but the Physics community is up to the task I think.

So what are we going to do about it?

The newest tool in the search for more information about Dark Energy is the Dark Energy Survey. Much like the starship Enterprise, in August the DES embarked on a 5 year mission to explore the universe. Unlike the Enterprise, it will probably not be able to seek out new life, and it will complete its mission without ever leaving Earth, using the Victor M. Blanco Telescope in Chile. Its goal is to map the southern sky with unprecedented resolution and detail.

Fermilab has a somewhat more detailed article (still accessible to a general audience) about how the DES will search for more information about Dark Energy, but basically it’s going to be looking for the effects of this expansion to more carefully measure its strength and observe its effects on objects in the universe such as galaxy clusters and supernovae.

So, the mystery continues, but we’re poised to learn a lot more about the universe in the coming years. There’s a lot of excitement that we could find the truth is even more exotic than we could have predicted. And, as always, the search for answers will no doubt lead to more interesting questions.

You are the 5%: The Mystery of the Missing Universe (Part I)

The title of this blog, “Fireside Science,” is of course a reference to Franklin D. Roosevelt’s Fireside Chats, where the President would communicate directly with the American public via radio. They listened, nestled comfortably in their living rooms beside their radios, while FDR explained big and scary things like the banking crisis and World War II, in a comforting and accessible way. The analogy suggested by our title is going to be especially relevant to this post because there are a couple of frightening things, which you may or may not be aware of, that I would like to talk about.

(1)    Everything that you’ve ever seen, heard, smelled, or felt is made up of stuff that only comprises 5% of the universe. For most scientists, that means everything you’ve ever studied- the entire vastness of knowledge and the blood, sweat, tears, triumph, and despair involved in those discoveries- can AT MOST describe 5% of the universe.

(2)    All of the large objects in the universe- galaxies and galaxy clusters- are not only moving farther apart from each other, but the rate at which things are getting farther apart is increasing. Eventually, all of the stars in the sky will be extinguished. The universe will be devoid of life, light, everything. Also, no one really has any idea why this expansion is happening.

Ok, that might have been a little melodramatic. Let’s break this down.

Dark Matter

In 1933, a Swiss astronomer named Fritz Zwicky was observing the motion of the Coma Galaxy Cluster. Based on the amount of light coming from the cluster, he estimated the total amount of matter in its galaxies. He then compared this to the amount of matter that must be present based on the speed of its galaxies. Based on the speed, the galaxies would have needed to have a mass 400 times that which could be accounted for by the visible light. Zwicky concluded that the galaxies must be held together by some kind of “dunkle Materie,” or Dark Matter, since it could not be seen visibly.

It turns out that Zwicky was very, very right. Astronomers and astrophysicists found places all over the universe where their observations could only be explained by “missing mass”- dark matter (although I contend that “Zwicky matter” would have sounded much cooler than “dark matter”).

With modern measurements, it turns out that dark matter accounts for 27% of the universe. Wow. That’s over 5 times the amount of “normal” matter—what you and I are made of.

So….what is it?

The person who answers this question definitively is going to get a Nobel Prize, so you can accurately call this the million-dollar question. There are a few things physicists could be sure of right from the start; first, it doesn’t interact electromagnetically, i.e. with light, but it does interact gravitationally. That accounts for two of the four fundamental forces—what about the other two? The strong force is responsible for keeping nucleons together, so that’s not really in play here, but physicists do think that dark matter interacts via the weak force, which is responsible for radioactive decay.

Thus, one of the primary candidates is some sort of weakly interacting massive particle—a WIMP (because we physicists also like to think we’re funny sometimes). Really, this is most likely a family of particles rather than single particle, such as the proposed supersymmetric particles. There are, however, other candidates, such as axions, as well are more exotic theories. The details are, of course, monumentally complicated, so everything here is just to give you a taste of what’s going on the dark matter world currently.

How do we figure out which of these theories is right?

The experimental search for direct detection of dark matter is really in its infancy, so you can expect to hear more and more about these experiments in the future. There are a lot of different experiments now, coming at the problem from all directions possible, so I’ll just describe a few basic methods here. One way is basically to fill a big tank with a heavy element, such as Xenon, and wait. Since the dark matter doesn’t interact electromagnetically, it won’t care about the electrons floating around, but it will eventually knock into the nuclei, releasing energy which can be detected. Another natural place to look for dark matter is in a machine specifically designed to blast detectors with particle soup where we can look for fun new physics- the Large Hadron Collider. Some people are getting a bit more creative though—such as a proposed experiment to find dark matter collisions with strands of DNA.

Ok so, 26% + 5%=31%. Where is the rest of the universe?

The rest of the universe- a whopping 69%- is made up of something called Dark Energy. The name is kind of misleading—dark energy isn’t directly related to dark matter in any way that we know of. It’s just called “Dark” because we have no idea what’s there. The pie chart of the universe might as well look like this:

Here be dragons

Dark Energy is a mystery all unto itself, which I’ll discuss in my next post- to be continued!

Some more reading about Dark Matter:

The Art of Darkness, by Katie Mack

Dark Matter Mysteries: a true game of shadows, by Stuart Clark

Exploring the Science of Dark Matter with the Cryogenic Dark Matter Search

Electricity from Heat: Thermoelectric Generators

As energy demands are rapidly increasing with developing countries like China and India continuing to industrialize, the need for sustainable clean energy sources is greater than ever. In addition to technologies that you are probably familiar with such as wind, solar, geothermal, and biomass, one you may not have heard of is thermoelectricity. Thermoelectric  generators (TEGs)  can turn heat into electricity without any moving parts. The video below from the Naked Scientists explains well what TEGs are, how they work, and why they could be extremely useful.

If you don’t have time to watch the video, here’s the key info:

When you heat up a thermoelectric material unevenly, positive or negative charges (depending on the material) move to build up a voltage, so if you put several of these materials together you can make an electric generator, shown in the picture below. These generators can be used to recover waste heat from just about anything you can think of: big things like power plants, cars, and  NASA spacecraft, but also small electronics like watches and cell phones.

Thermoelectric Generator

Cars are probably the place where you’re most likely to see these popping up in the next several years. They’re a great candidate for TEGs for several reasons. First, as the image below shows, not very much of your engine’s energy goes towards actually moving your car forward. Any of the energy lost to heat that could be recovered would be a big help to your gas mileage. Additionally, the exhaust pipe of a car provides the perfect place for a TEG. One side can be heated by the exhaust, and the other cooled by the surrounding air.

Fuel Economy losses

The problem is, TEGs not generally very efficient, and the cost of materials is too high to make widespread use economical given these low efficiencies. One way to make TEGs more efficient is engineering materials very carefully on the scale of nanometers- 6,000 times smaller than a human blood cell, or about 5-10 times bigger than an atom. It’s really difficult to fathom just how small the structures I’m talking about are since they’re so far removed from what we can see in our daily life. The image below is a good attempt at putting this scale into context: If a nanoparticle was the size of a football, a kiwi would be as big as the world. However, most instruments that measure the thermoelectric properties of materials- like the proportionality factor between how much of a temperature difference there is and how big the voltage you get is- are measured on the scale of millimeters, one million times larger than a nanometer.

Nanoscale

Thus, we need more precise instruments to understand the complicated physics happening at such a small scale. This is the motivation for my small but fundamental contribution for making high efficiency TEGs. I’m developing and using instrumentation which can measure this proportionality factor on a nanometer scale, so you can map out how it changes across the different nanostructures in the material and try to explain the results using physical laws. Getting a better understanding of these properties on a small scale can help engineers know what type of structures to make to increase the efficiency of a TEG.

Hopefully soon you will start seeing TEGs on your car or hear about them being used in your local power plant, but in the meantime, you can actually buy (or build!) your own thermoelectric generator. For example, they’re pretty useful when camping; the video below of a TEG being used on a small stove to power a USB connection which of course can then power a flashlight, IPhone, or any other USB device.

Fireside Science

Welcome to Fireside Science: SciFund Challenge’s Guide to Life, the Universe, and Everything!

I’m proud to introduce a new blog brought to you by a group of graduates of the first SciFund Outreach course. Our goal is to bring you stories from all corners of the world of science and engineering. As our sub-heading suggests, the majority of our contributors will explore topics in the life sciences such as cell biology, ecology, and herpetology, but we’ll mix things up with posts from writers of all disciplines, taking you from the microscopic world of DNA and cell biology, unraveling the mysteries of life, all the way to the farthest reaches of the universe with astrophysics, searching for a deeper understanding of the very spacetime we exist in.

For our first post, I’d like to introduce you to our contributors. Below I’ve listed some information about several of us (including myself, the rogue physicist of the bunch), such as topics that we are likely to blog about. However, since this is a new blog, we’d love to hear what YOU want us to write about. If you’re particularly interested in any of the topics below, let us know! Further, if there’s anything not listed below that you’ve always wanted to know more about, definitely ask us about it in the comments. Sometimes science can be a pretty small world, and if none of us are knowledgeable about what you’d like to hear more about, chances are one of us knows someone who is!

Thanks for reading, and welcome again to Fireside Science!

Jenna
@petitrenard6

Bradly Alicea
Research Postdoc
Research Interests: Systems Biology, Brain and Behavior, Artificial Life, Evolutionary Theory, Complexity and Computation, Scientific Innovation
Other Possible Topics: open-source science, the cognition, culture, and ideology of scientific ideas, and the technical and philosophical concepts behind measurement, modeling, and technology more accessible to other domains of science
Other Info:
Personal Website: https://www.msu.edu/~aliceabr
Synthetic Daisies: https://syntheticdaisies.blogspot.com
Academia.edu profile: https://independent.academia.edu/BradlyAlicea

Claudia Baider
Herbarium Officer
Research Interests: Conservation, invasive species, plant animal interactions, plant taxonomy
Other Possible Topics: field biology experiences, living in the forest, the daily life of a scientist
Other Info: Claudia likes to cook, especially trying new recipes, and she has a ‘wild’ cat (picked as tiny kitten in the forest).

Becky Bola
Postdoctoral Fellow, The Paterson Institute of Cancer Research in Manchester UK
Research Interests: Cell biology, Preclinical Pharmacology, more specifically apoptosis and metabolism (not the two together)
Other Possible Topics: cell migration and trafficking
Other Info: Becky has a little boy and loves sports, specifically TaeKwon-Do– in her spare time she runs a club!

Abby Buchwalter
Postdoctoral Fellow, The Salk Institute for Biological Studies in La Jolla, CA, US
Research Interests: cell biology, specifically nuclear organization in normal / diseased / stem cells
Other Possible Topics: cell biology, stem cells, cancer, intra- and inter- cellular communication; science / culture / policy / education
Other Info: Abby loves microscopes, running, knitting, and peanut butter.

Frederik Feys
PhD student, Free University of Brussels, Belgium
Research Interests: placebo effect of health interventions
Other Possible Topics: role of expectancies on our health
Other Info: Frederik has two kids, plays guitar in a band, and loves walking in nature.

Ruth MacKinnon
Research Fellow at St Vincent’s Hospital, Melbourne
Research Interests: chromosomes and genetics, especially in cancer
Other Possible Topics:genomics, cancer genomics, chromosomes, the life of a scientist (trials and triumphs), and background into some scientific discoveries.
Other Info:
Ruth has a blog about her research here https://chromosomesandcancer.com/
and can be found on twitter @ruthnmackinnon. Her main past-time is as a musician (bassoonist) in the Essendon Symphony Orchestra, and she has three kids, a dog, and two cats.

Lisa Regula Meyer
Instructor, Eastern Gateway Community College and Kent State
Research Interests: Invasive plant-Native amphibian interactions
Other Possible Topics: Invasive species, Amphibian ecology, Conservation, Education, Citizen science
Other Info: Writer of all sorts, educator, researcher, and parenting partner

Katharine Servidio
Graduate Research Assistant – University of Georgia/Coweeta LTER
Research Interests: Amphibians, trophic cascades, ecosystem function
Other Possible Topics: General herpetology, general entomology, trophic cascades, invasive species, Amphibian ecology & conservation, population dynamics, the life of a graduate student
Other Info: Katharine is a musician (brass quartet), an avid runner, and a reader of all things.

Barbara Shih
Research Associate at University of Manchester
Research Interests: Vitamin D, DNA damage, sun exposure, keloid and Dupuytren’s disease
Other Info: Barbara enjoys board games, video games, and drawing.

Jenna Walrath
Ph.D. Student, Dept. of Physics, University of Michigan
Research Interests: Solid state physics: nanostructured semiconductors, thermoelectric materials (a type of clean energy)
Other Possible Topics: Interesting work in any and all fields of physics: the search for new particles, dark energy, new states of matter, advances in applied physics such as clean energy research, medical physics, anything else that sounds cool
Other Info: Jenna has two cats and loves swing dancing, bowling, and yoga in her spare time. She can be found on twitter @petitrenard6.