The Fermi Paradox

The Fermi Paradox

For a great example of science communication (and some fascinating thought puzzles) take a look at Wait But Why’s The Fermi Paradox, which addresses the question: where is all the other intelligent life out there?

(NSFW language in the article)


Scientists don’t need to wear a white lab coat to talk about science

Scientists don’t need to wear a white lab coat to talk about science

I had a scientist request a bunch of lab gear to take into a classroom just this week (that they don’t normally use in their job). It can be fun playing dress-up, certainly, but it’s interesting to think about the repercussions of having such an authoritative uniform on public perception

How to get researchers involved in public engagement

A researcher at my institution has written a blog for the Wellcome Trust about the public engagement event we ran from February-May 2014: Magnificent Microbes. 

Hints on best practice include:

  1. Ask questions! Children can get distracted quite easily so the best way to keep their attention is to ask them what they know. This will also prevent you from telling them things that they know already.
  2. Make your activities as hands-on as possible – really enable your audience to get involved.
  3. Think about your target audience; can you present the exhibit to both young children and adults? How will you tailor what you say to suit them?
  4. Make your exhibit relevant. There is no better way to engage your audience, particularly children, than to make them realise how your research affects them personally. For instance, we use the formation of plaque on your teeth as an example of how biofilms are medically important. This allows us to engage with children by asking them how often they brush their teeth and why they think it’s necessary.
  5. Calculate the quantities of consumables you will need. It doesn’t do any harm to overestimate slightly, but be prepared to be flexible with what you have. In our case we ended up having to ask families to share particular props, as we ran short towards the end of the event.
  6. Don’t over simplify the exhibit to accommodate children. I was really pleasantly surprised at just how much the kids took away from what we told them.

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!

The Amazing Spider-Man 2 and the spirit of invention

I saw the Amazing Spiderman 2 over the weekend, and besides the great chemistry of the leads and thrilling soundtrack there was one thing I particularly liked and that was the home-grown science, which I thought was a great representation of engagement with science as a useful skill.

Peter Parker is a smart kid, there’s no doubt about that. He makes his costume and web-shooters in his basement, in secret, and it’s those as much as his spidey sense that make him a great crimefighter. When he goes up against a new supercharged villain named Electro he soon finds out that his web-shooters aren’t up to handling the massive electric charges: they fizzle and pop and become pretty useless – a problem when you really need to get anywhere in NYC faster than a speeding cab.


So, what does he do? Goes home and pulls up a popular science video “Batteries, the Pluses and Minuses” by Dr Jallings, Science Investigator. Armed with this newfound knowledge, a scuba mask, and varying sizes of batteries he tries his best to adapt his shooters to handle larger and larger currents, with predictably explosive results. He doesn’t actually solve the problem until his sharp-minded girlfiend Gwen Stacy (who presumably stayed awake in that particular science lecture) reminds him that he needs to magnetise them, which they do with the help of a cop and some jumper cables, and from then on Electro doesn’t stand a chance.

So what do I love so much about this? It’s not the science itself – I’m no electrical engineer and wouldn’t have been able to solve the problem if my life depended on it. No, what I love is the fact that they have consistently taken time to show on-screen Peter’s curiosity and exploration and the benefits it brings him. What better hero to look up to than one who plays with things in his own basement, looking up science videos and flipping through books? Batman may have Morgan Freeman to provide him with whatever fancy tech he needs, but when it comes to superheroes give me a teenage geek every time.

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!

A Rough Guide to Spotting Bad Science

Over at Compound Interest they’ve put together a handy Rough Guide to critically reading science reporting.



Might have to invest in a poster for the wall of my office!