Tag Archives: science

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!

The Water Cycle and The Future

I’ve always loved water. My favourite sport is swimming, because of how it feels to have water holding you up. And when I was young, any time it rained I’d run outside and just walk for ages in the rain: I loved the smell and the cool of it. Admittedly, rain was a rarity in my childhood, since I grew up in New Mexico in the US, which is all mountains and desert. I can see why here in Ireland, where rain is so much more common, you see fewer people rushing to the streets each time it rains. But in my desert home, one of the things I found fascinating is that water has a story, a history just like us, it has somewhere it came from and somewhere it’s going. When we see the rain fall, it’s evaporated from the ground, from lakes, from the sea. And that same rain will be absorbed by the ground and stay in it before rising again, or freezing into ice caps, or melting and flowing again to the sea. Here in Ireland, the clouds come in off the ocean, so the water in our rain is evaporated sea water.

We can think of the water on the world like the water in our own bodies. We can run and get sweaty, and the water on our skin evaporates away. We can drink in water, filling our insides the same way that aquifers under the surface of the earth are filled with water. And then we can release that water given time, the same way that solid land loses some of its water to the seas. But because the earth is so big, it also has weather on its surface, clouds and rainfall, and as far as I know I’ve never sweated enough to make it rain.

But how quickly water moves through this cycle depends on the weather, the same way it does for our bodies. You sweat more when it’s hot and humid, like now, and less if it’s cold or dry, right? Well water is affected the same way, by how warm the surface of the earth is. In hot conditions, more water will evaporate off the earth’s surface and off of plants, which can stimulate more weather like rain and thunderstorms… unless it’s very dry! So where I grew up, desert plants have to work really hard to hang onto water, because it’s such a precious resource and the heat and dryness cause it to go away really quickly. Plants here don’t have that issue, as there is plenty of water to go around!

We are changing how the water cycles through our world, though. When people build dams, cut down forests, pasture animals, build cities, or burn fuel for energy, that changes where water can flow and how long it stays in the air. All of our activities affect the flow of water through the sky, the sea, and the earth.

In fact, greenhouse gases from our human civilization are causing the atmosphere to trap more heat from the sun, so that our planet is gradually warming up. It’s a slow process, taking decades for the world’s temperature to rise even a degree on average, but it’s been going on for awhile now. So even though we are trying to switch to solar power away from things like coal power, our planet will keep warming up. Sea levels will go up, and we’ll have warmer summers and rainier winters. Here in Ireland, it might be nice, as long as you don’t live right on the sea. But in New Mexico, it’s already difficult to grow food and stay cool during the summer, so the extra heat might make it very hard for people to live there. But the important thing about the future is understanding it so you can plan accordingly… for example, by moving to Ireland!

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!

Top Ten Popular Science Books

I recently got a request to recommend some popular science books that don’t assume any scientific knowledge on the part of the reader. I was surprised at how hard it was to think of books, because to be honest, most pop science books do seem to assume that you have some fluency in science ideas or jargon, if at a lesser level than a scientist would. I’ve read some very popular books about biological topics that I found dry or hard to get through, because even though I’m a scientist I don’t know very much biology. But I came up with the following ten books, which explore different aspects of science in strongly accessible ways:

These books will give a nice overview of some of the great stuff that’s out there in popular science reading. (Note: the links above are affiliate links, just something we’re trying out!) Of course, I’m always interested in other people’s recommendations too, so have at it in comments if you like!