Tag Archives: physics

When Your Science Hero is Problematic

We all have heroes, people we look up to and whose achievements spur us on to do our own personal best. And, especially in this era where women are saying #metoo and finally being heard, we have probably all had the experience of finding out that one of our heroes has done some less than heroic things. This has come up a lot for me recently with the deaths of some very famous scientists and science fiction writers, men I greatly admired when I was a kid, who I’m now discovering were frequently awful to women (i.e., people like me).

I think this happens more than usual in science, a traditionally male-dominated field where a culture of elitism and privilege has been embedded for a long time. And it’s tempting to view things in black and white: either my hero is amazing for their achievements or they are garbage for their behaviour. We know in our personal lives that people are multi-faceted, yet we’re slow to allow public figures that same understanding. If a famous male scientist discovers lots of things, and is a great collaborator with other men but acts differently toward women, consciously or unconsciously, how are we meant to think about that?

As a physicist who loves to write, I’ve had to consider this before, because one of my early science heroes was Richard Feynman. Feynman was a brilliant theoretical physicist, a Nobel laureate, and worked on the Manhattan project building the atomic bomb in my hometown of Los Alamos. He also wrote a series of very enjoyable popular science books, which were also quite personal and effortlessly engaging. A quote from an interview that immediately stuck with me:

Omni: As we came back to the office, you stopped to discuss a lecture on color vision you’ll be giving. That’s pretty far from fundamental physics, isn’t it? Wouldn’t a physiologist say you were ‘poaching’?

Feynman: Physiology? It has to be physiology? Look, give me a little time and I’ll give a lecture on anything in physiology. I’d be delighted to study it and find out all about it, because I can guarantee you it would be very interesting. I don’t know anything, but I do know that everything is interesting if you go into it deeply enough.

As someone who is omnivorous about knowledge, I found that quote resonated with me deeply. Science is fascinating because it shows us how the world works, how things which might appear separate are deeply connected, and the overlapping intricacies behind the everyday we take for granted. I now do my research on nanoscience, a strongly interdisciplinary field that draws from chemistry, electrical engineering, materials science, and plenty more beyond the physics that I got my degrees in. I admired Feynman for not letting other people dictate the questions he could ask, for being a physicist in what felt like a subversive and wide-ranging way. He was also famous for his sense of humour, his love of non-scientific things like playing bongos, and for generally not being as formal and rigid about anything as physicists tend to be.

The author having a Feynman bongo moment at the No-Ball Prizes. Photo by Ian Bowkett.

Of course, if you read Feynman’s books you’ll also find less inspiring stories, if you are a female scientist. He writes about doing his calculations in a Hooters, negging women in bars, and pretending to be an undergraduate to pick up grad students’ wives. This is less subversive, and more what we might generously call ‘of a time’. Feynman did plenty to promote the status of women in physics, encouraging his own sister to study it and eventually get a PhD. But reading through these differing accounts of his behaviour, female physicists are left wondering whether this great man of science would have seen them as colleagues and equals, or as prey.

I still find a lot in Feynman to look up to, as a physicist who did amazing work but cared about communication and didn’t give in to pressure to conform. However I can still acknowledge the women he mistreated, or perhaps even drove out of the field which is a terrible loss to science. He had a complexity to him, and my initial hero-worship of Feynman when I was younger has been replaced by equally complex feelings, of respect for his scientific and communication work alongside frustration at his mistreatment of women. But there’s no such thing as a perfect hero anyway, and if I needed one in physics, I might be waiting a long time. We have many historical women in physics to look up to, like Lise Meitner or Emmy Noether, and yet often these women were denied resources and opportunities that their male colleagues had, which can make them feel like amazing but also tragic figures. I would hope that women working in science today can be heroic without the tragedy.

Perhaps looking for heroes in science is a fundamentally flawed endeavor. Science is at its heart collaborative, and the sheer scope of human knowledge means that it is impossible for one person, toiling alone, to conquer it all. We must talk to each other, work together, and build on existing work, as famously stated by Isaac Newton: “If I have seen further it is by standing on the shoulders of giants.” The great man theory is as flawed when it comes to science as it is when it comes to history. We all seek out role models, but we must recognize that they worked with others, seen and unseen, and that science is a societal effort and not the work of a lone genius.

While Feynman is long gone, there are other scientists still living, still contributing, and still behaving badly. It’s important that we not let them off the hook. Feynman lived decades ago, and certainly the standards of behaviour were different then, but today’s harassers and discriminators have no such excuse. If science is truly a collaborative effort, then it loses strength every time a person is pushed out of science by harassment. We can have complicated feelings about prominent scientists of the past, but there are a lot of people working in science today who are doing it right, and can serve as inspirations.

For example, tomorrow is the first ever LGBT STEM day, being celebrated with events around the world. Our Irish LGBT STEM network, House of STEM, has done so much to organise and promote this event, and founder Shaun O’Boyle explains why it’s desperately needed here:

The past is full of problematic yet successful scientists. Yet I’m hopeful that the future will have a broader array of amazing scientists, working together, who are also amazing people.


Innovative Technologies

I work in nanoscience, and a lot of new materials and devices are developed where people ask, what is going to be the application of this? Can this displace an established technology (like silicon computer chips) or create a new market? And I was recently reminded of a great quote in response:

The principal applications of any sufficiently new and innovative technology always have been—and will continue to be—applications created by that technology.

That was said by Herbert Kroemer in his Nobel lecture, and it bears thinking about in many contexts both within science and in the broader world. When you’re doing something new, it may not fit neatly into the established hierarchies of technology, science, or industry. That can be good, and in fact it can be groundbreaking, like a present you didn’t know you wanted! Of course, it’s still important to think about how your work fits into the broader picture as it already is, but I think it’s always good to get a reminder to check your premises, that innovation can create its own new niches.

Sweat The Small Stuff

Let’s talk about science! Literally, here I am talking about science, the quantum world, scientists, and answering audience questions from a kindly bunch at Pint of Science this May in Dublin. There is also a bit of a surprise in the middle.

Flatland and Extra Dimensions

What would life be like if you lived in two dimensions instead of three?

Back when I posted about popular science books for non-scientists, one of the suggestions I got after the fact was Flatland: A Romance of Many Dimensions, the 19th century classic by Edwin A. Abbott. Which is absolutely worth reading, and a great example of what I love in science writing (or science fiction): an idea that makes you change your whole perspective on the world and reimagine it from a different point of view.

The idea behind Flatland is this: what would it be like if the world we inhabited were flat instead of 3D? You can imagine it as living within a piece of paper, or on the surface of a table. The notion of up and down would be meaningless; we’d only have left and right, and front and back. So we’d be moving in two dimensions rather than three, and we’d also perceive everything around us to have only two dimensions. There wouldn’t be any going over a fence, or peeking under a door. If a thing blocked your way, it would block it completely, and everything behind it would be completely invisible. Of course, you wouldn’t be able to pass through things in Flatland, the same way you can’t in the real world. So if a person stopped directly in front of you, you’d have to pass to either side, or not at all.

There’s a lot of social commentary in Flatland as well, satire aimed at Victorian England that comments on gender divisions, class hierarchies, and dogmatism against new ideas. It’s worth a full read for that, though its examination of spatial dimensions is what’s kept it famous.

Life in Flatland may seem like an academic abstraction. But actually, while our world is three-dimensional, there are some things in it which effectively have only two dimensions, especially in the world of nanoscience. The touted wonder material graphene is effectively two-dimensional, because in the third dimension it’s only one atom thick. That means that electrons moving through graphene are effectively in a two-dimensional environment, a Flatland, and can’t use the third dimension to go around each other. More two-dimensional materials are being discovered every day, and taking one dimension of a material to the nanoscale while leaving the others large changes the physical laws in that material significantly!

And what if there were more dimensions to the world? What if instead of three dimensions to space, there were a fourth, or a fifth? In that case, life here in three dimensions would seem like Flatland, without the fourth dimension to move through. Some physicists studying string theory think there may in fact be additional spatial dimensions, but that they must be curled up within the three we know in order to be undetectable.

So the idea of Flatland, a world where there are only two dimensions instead of the usual three, isn’t just a science fiction classic, it’s also a valuable thought experiment that ties into both nanoscience and string theory!

Reynolds’ World

What’s it like for little things like bacteria to move around? How do they swim from place to place?

We know that swimming feels different from walking. Part of it is the feeling of being suspended, where instead of the firm solidity of the earth and the  insubstantial give of air, we have the water on all sides, supporting not just our feet but our legs, arms, and body. But also, it’s a lot harder to move through water! The same quality that makes us feel supported also impedes movement, so that even a very efficient swimmer will be easily outpaced by someone strolling along on dry land.

Scientists have a way to quantify that  difference, using a measure called the Reynolds number. The Reynolds number compares how strong inertial forces are in a fluid, which come from the particle size and the weight of the particles, with the viscosity of the fluid. If a fluid has low inertial forces compared to its viscosity, it has a low Reynolds number, and if it has high viscosity compared to its inertial forces, then its Reynolds number is low. So fluids with a high Reynolds number are easier to move through, and fluids with a low Reynolds number are harder to move through. The pitch of the Trinity pitch drop would have a very low Reynolds number! And fluid flow in high Reynolds number environments tends to have more chaos, vortices and eddies that can arise because of how easy it is to move light things that don’t stick together, like molecules of air.

So it turns out that what strategy you use to move in a low Reynolds number environment is different from what you’d use in a high Reynolds number environment. Of course, we already know that, because if we try to walk or run in water, it doesn’t work very well! Running is a great way to get around when you are moving through thin air with the solid ground beneath you, but humans have developed various modes of swimming for water, that take advantage of our anatomy and account for the different nature of water.

But remember, we are largely made up of water! So what about our moving cells and bacteria, which have to get around in a low Reynolds number environment all the time? And keep in mind that our cells are very small, subject to molecular forces and a lot closer to the size of water molecules than we are. Not surprisingly, there are different forms of swimming that take place in our cells. One of the most common is using a rotating propeller, a little like the blade on a helicopter, to move forward. These structures are called flagella and are common on the surface of various types of cells, to use rotary motion as a way of easily moving through the high Reynolds number environment.

So the next time you are walking around with ease, take a moment to imagine how different it is for everything moving from place to place in and around your cells. It is a whole different world, right inside our own!

Quantum Worldview

I have always loved the kind of science fiction where you think about a world that is largely like our own, but in some fundamental way different. What if we all lived underwater, or if the force of gravity was lower, or if the sun were a weaker star? To me, that’s what the world of quantum physics is like: in a lot of ways it’s similar to our own world, in fact it’s the basis of our world! But it’s also crazy and strange. So what would it be like if we were quantum creatures, if we could actually see how everything around us is quantized?

Well first, there’s what it means to be quantum. A quantum of anything is a piece that can’t be subdivided any further, the smallest possible unit. But this implies a sort of graininess, where rather than a continuous stream of, say, light, we start to see at the small scale that light is actually composed of little chunks, quanta of light. Imagine being able to see how everything around you is made of discrete pieces, from light to sound to matter. When the sun came up, you’d see it getting lighter in jumps. When you turn up your music, you’d hear each step of higher volume. And as your hair grew, you’d see it lengthening in little blips.

And at the quantum scale, the wave nature of everything becomes indisputably clear. We normally think of waves as something that emerges from a lot of individual objects acting together, like the water molecules in the sea, or people in a crowd. But if you look at quanta, you actually find that those indivisible packets of light or sound or matter are also waves, waves in different fields of reality. That’s hard to get your head around, but think of it this way: as a quantum wave, if you passed right by a corner, you could actually bend around the back of it a little the way that ripples going around a rock in water do. Things like electrons and photons of light actually do this, so for example the pattern below is made by light going through a circular hole, and the wave diffraction is clearly visible.

Amazingly, as a wave, you could actually have a slight overlap with the person next to you. This gets at something that’s key to quantumness: the probabilistic nature of it. Say I thought you were nearby, and I wanted to measure your position somehow to see how close you were to me. I’d need to get a quantum of something else to interact with you, but because it would be a similar size to you, it would slightly change your position, or your speed. We don’t notice the recoil when sound waves bounce off us in the macroscale world, but if we were very small we would! So there is actually a built in uncertainty when dealing with quantum objects, but we can say there’s a probability that they are in one place or another. So as a quantum creature, you can think of yourself as a little wave of probability, that collapses to a point when measured but then expands out again after. When I’m not measuring you, where are you really? Well I can’t say physically, and this is why you can have a little wave overlap with your neighbour without violating the principle that you can’t both be in the same place at the same time.

And imagine that you’re next to a wall. As a wave you may have a little overlap of probability with that wall. And if the wall is thin enough, as a quantum object there is actually some chance that you’ll pass through the wall entirely! This is called quantum tunnelling, and actually it’s happening all the time in the electronics inside your phone. Modern microelectronics work in part because we can use effects from the quantum world in our own, larger world!

It’s difficult to imagine a world where everything happens in discrete chunks, where I can see myself as a wave, where I don’t know where I am until someone else interacts with me. But this is the world at the quantum scale, and it’s not science fiction!

Thermoelectrics and the Movement of Electrons

Often the big picture, like a river winding down a canyon or flashes of lightning in the sky, can be understood by looking at the small-scale behavior of each component, like molecules of water rushing to lower elevation or electrons seeking to equalize potential. I’ve always liked that approach to understanding nanoscale physics phenomena, like electricity or heat. But if you think about it, since electricity is the movement of charge carriers in response to an electric field, and hotter particles also move around more, shouldn’t there be some interaction between the two? Can something develop an electric current as a result of being hot? Or can driving electricity result in the generation of heat?

If you’ve ever felt an electronic device heat up in your hand or on your lap, then you know the answer is yes! Running an electric current through some materials, like resistors, generates waste heat, which is a big practical problem for electronics manufacturers. But there are some materials that can do the opposite, converting heat to electricity. Extracting usable electricity from waste heat is especially impressive when you think about the reduction in entropy involved; turning the high-entropy disordered heat back into an ordered electrical potential is a strong local reduction of entropy. This is how 90% of the electricity in the world is generated, but at a low efficiency. Materials where a temperature difference creates an electrical potential are called thermoelectrics, and in addition to being really practically important, thermoelectrics are a great illustration of how important it is to understand what’s happening at the nanoscale.

The most common thermoelectric device is one where two different metals are pressed together, creating a junction. Each metal is a conductor, and will have its own electrons, which can freely move across the junction. But the electrons experience different forces in each conductor: they may find it easier or more difficult to move through the material, based on the physical properties of the metal itself. So applying a voltage across the junction will affect the electrons in each material differently, and can cause one metal’s electrons to move faster than the other’s. This difference in electron speeds, or a difference in how easily the electrons transfer their energy to the atomic nuclei in the metal, or just slow diffusion of electrons across the junction, can all lead to a temperature difference between the two metals. Thus heat can be produced at the junction, and it can even be removed given the right material properties. Heat generation or removal at an electrical junction is called the Peltier effect, and is the basis of some nanoscale refrigerators and heat pumps.

Conversely, if a temperature difference already exists across a junction of two conductors, you can imagine the faster moving electrons in the hotter material, interacting with the slower moving electrons in the colder material at the junction. For the right combination of material properties, an electrical potential will be induced by the differing temperatures, which is called the Seebeck effect. But it’s the same mechanism as the Peltier effect above, namely that both heat and electric fields induced the movement of charge carriers, and so of course the two effects have some interaction with each other.

It’s not just metals that exhibit thermoelectric behavior, though. Semiconductors can also be used as thermoelectrics, and actually have a broader range of thermoelectric behavior because their carrier concentration varies more widely than that of metals. Heat and electric field affect the charge carriers in every material, it’s just that some materials have properties that result in a more interesting and usable phenomenon.

Thermoelectric materials can be used as heat pumps and refrigerators, as I mentioned above. But the thermoelectric effect can also be used to measure temperature, by putting two metals that react differently to temperature together and then measuring the induced electric potential. This is how thermocouples work, which are incredibly common. And it all comes from the fact that both heat and electricity cause motion at the nanoscale.