Tag Archives: science communication

Outreach Talk on Math’s Role in Physics

Tonight is “Culture Night” in Copenhagen, the night when the city throws open its doors and lets the public in. Museums and hospitals, government buildings and even the Freemasons, all have public events. The Niels Bohr Institute does too, of course: an evening of physics exhibits and demos, capped off with a public lecture by Denmark’s favorite bow-tie wearing weirder-than-usual string theorist, Holger Bech Nielsen. In between, there are a number of short talks by various folks at the institute, including yours truly.

In my talk, I’m going to try and motivate the audience to care about math. Math is dry of course, and difficult for some, but we physicists need it to do our jobs. If you want to be precise about a claim in physics, you need math simply to say what you want clearly enough.

Since you guys likely don’t overlap with my audience tonight, it should be safe to give a little preview. I’ll be using a few examples, but this one is the most complicated:

I’ll be telling a story I stole from chapter seven of the web serial Almost Nowhere. (That link is to the first chapter, by the way, in case you want to read the series without spoilers. It’s very strange, very unique, and at least in my view quite worth reading.) You follow a warrior carrying a spear around a globe in two different paths. The warrior tries to always point in the same direction, but finds that the two different paths result in different spears when they meet. The story illustrates that such a simple concept as “what direction you are pointing” isn’t actually so simple: if you want to think about directions in curved space (like the surface of the Earth, but also, like curved space-time in general relativity) then you need more sophisticated mathematics (a notion called parallel transport) to make sense of it.

It’s kind of an advanced concept for a public talk. But seeing it show up in Almost Nowhere inspired me to try to get it across. I’ll let you know how it goes!

By the way, if you are interested in learning the kinds of mathematics you need for theoretical physics, and you happen to be a Bachelor’s student planning to pursue a PhD, then consider the Perimeter Scholars International Master’s Program! It’s a one-year intensive at the Perimeter Institute in Waterloo, Ontario, in Canada. In a year it gives you a crash course in theoretical physics, giving you tools that will set you ahead of other beginning PhD students. I’ve witnessed it in action, and it’s really remarkable how much the students learn in a year, and what they go on to do with it. Their early registration deadline is on November 15, just a month away, so if you’re interested you may want to start thinking about it.

Breaking Out of “Self-Promotion Voice”

What do TED talks and grant applications have in common?

Put a scientist on a stage, and what happens? Some of us panic and mumble. Others are as smooth as a movie star. Most, though, fall back on a well-practiced mode: “self-promotion voice”.

A scientist doing self-promotion voice is easy to recognize. We focus on ourselves, of course (that’s in the name!), talking about all the great things we’ve done. If we have to mention someone else, we make sure to link it in some way: “my colleague”, “my mentor”, “which inspired me to”. All vulnerability is “canned” in one way or another: “challenges we overcame”, light touches on the most sympathetic of issues. Usually, we aren’t negative towards our colleagues either: apart from the occasional very distant enemy, everyone is working with great scientific virtue. If we talk about our past, we tell the same kinds of stories, mentioning our youthful curiosity and deep buzzwordy motivations. Any jokes or references are carefully pruned, made accessible to the lowest-common-denominator. This results in a standard vocabulary: see a metaphor, a quote, or a turn of phrase, and you’re bound to see it in talks again and again and again. Things get even more repetitive when you take into account how often we lean on the voice: a given speech or piece will be assembled from elementary pieces, snippets of practiced self-promotion that we pour in like packing peanuts after a minimal edit, filling all available time and word count.

“My passion for teaching manifests…”

Packing peanuts may not be glamorous, but they get the job done. A scientist who can’t do “the voice” is going to find life a lot harder, their negativity or clumsiness turning away support when they need it most. Except for the greatest of geniuses, we all have to learn a bit of self-promotion to stay employed.

We don’t have to stop there, though. Self-promotion voice works, but it’s boring and stilted, and it all looks basically the same. If we can do something a bit more authentic then we stand out from the crowd.

I’ve been learning this more and more lately. My blog posts have always run the gamut: some are pure formula, but the ones I’m most proud of have a voice all their own. Over the years, I’ve been pushing my applications in that direction. Each grant and job application has a bit of the standard self-promotion voice pruned away, and a bit of another voice (my own voice?) sneaking in. This year, as I send out applications, I’ve been tweaking things. I almost hope the best jobs come late in the year, my applications will be better then!

The Winding Path of a Physics Conversation

In my line of work, I spend a lot of time explaining physics. I write posts here of course, and give the occasional public lecture. I also explain physics when I supervise Master’s students, and in a broader sense whenever I chat with my collaborators or write papers. I’ll explain physics even more when I start teaching. But of all the ways to explain physics, there’s one that has always been my favorite: the one-on-one conversation.

Talking science one-on-one is validating in a uniquely satisfying way. You get instant feedback, questions when you’re unclear and comprehension when you’re close. There’s a kind of puzzle to it, discovering what you need to fill in the gaps in one particular person’s understanding. As a kid, I’d chase this feeling with imaginary conversations: I’d plot out a chat with Democritus or Newton, trying to explain physics or evolution or democracy. It was a game, seeing how I could ground our modern understanding in concepts someone from history already knew.

Way better than Parcheesi

I’ll never get a chance in real life to explain physics to a Democritus or a Newton, to bridge a gap quite that large. But, as I’ve discovered over the years, everyone has bits and pieces they don’t yet understand. Even focused on the most popular topics, like black holes or elementary particles, everyone has gaps in what they’ve managed to pick up. I do too! So any conversation can be its own kind of adventure, discovering what that one person knows, what they don’t, and how to connect the two.

Of course, there’s fun in writing and public speaking too (not to mention, of course, research). Still, I sometimes wonder if there’s a career out there in just the part I like best: just one conversation after another, delving deep into one person’s understanding, making real progress, then moving on to the next. It wouldn’t be efficient by any means, but it sure sounds fun.

Alice Through the Parity Glass

When you look into your mirror in the morning, the face looking back at you isn’t exactly your own. Your mirror image is flipped: left-handed if you’re right-handed, and right-handed if you’re left-handed. Your body is not symmetric in the mirror: we say it does not respect parity symmetry. Zoom in, and many of the molecules in your body also have a “handedness” to them: biology is not the same when flipped in a mirror.

What about physics? At first, you might expect the laws of physics themselves to respect parity symmetry. Newton’s laws are the same when reflected in a mirror, and so are Maxwell’s. But one part of physics breaks this rule: the weak nuclear force, the force that causes nuclear beta decay. The weak nuclear force interacts differently with “right-handed” and “left-handed” particles (shorthand for particles that spin counterclockwise or clockwise with respect to their motion). This came as a surprise to most physicists, but it was predicted by Tsung-Dao Lee and Chen-Ning Yang and demonstrated in 1956 by Chien-Shiung Wu, known in her day as the “Queen of Nuclear Research”. The world really does look different when flipped in a mirror.

I gave a lecture on the weak force for the pedagogy course I took a few weeks back. One piece of feedback I got was that the topic wasn’t very relatable. People wanted to know why they should care about the handedness of the weak force, they wanted to hear about “real-life” applications. Once scientists learned that the weak force didn’t respect parity, what did that let us do?

Thinking about this, I realized this is actually a pretty tricky story to tell. With enough time and background, I could explain that the “handedness” of the Standard Model is a major constraint on attempts to unify physics, ruling out a lot of the simpler options. That’s hard to fit in a short lecture though, and it still isn’t especially close to “real life”.

Then I realized I don’t need to talk about “real life” to give a “real-life example”. People explaining relativity get away with science fiction scenarios, spaceships on voyages to black holes. The key isn’t to be familiar, just relatable. If I can tell a story (with people in it), then maybe I can make this work.

All I need, then, is a person who cares a lot about the world behind a mirror.

Curiouser and curiouser…

When Alice goes through the looking glass in the novel of that name, she enters a world flipped left-to-right, a world with its parity inverted. Following Alice, we have a natural opportunity to explore such a world. Others have used this to explore parity symmetry in biology: for example, a side-plot in Alan Moore’s League of Extraordinary Gentlemen sees Alice come back flipped, and starve when she can’t process mirror-reversed nutrients. I haven’t seen it explored for physics, though.

In order to make this story work, we have to get Alice to care about the weak nuclear force. The most familiar thing the weak force does is cause beta decay. And the most familiar thing that undergoes beta decay is a banana. Bananas contain radioactive potassium, which can transform to calcium by emitting an electron and an anti-electron-neutrino.

The radioactive potassium from a banana doesn’t stay in the body very long, only a few hours at most. But if Alice was especially paranoid about radioactivity, maybe she would want to avoid eating bananas. (We shouldn’t tell her that other foods contain potassium too.) If so, she might view the looking glass as a golden opportunity, a chance to eat as many bananas as she likes without worrying about radiation.

Does this work?

A first problem: can Alice even eat mirror-reversed bananas? I told you many biological molecules have handedness, which led Alan Moore’s version of Alice to starve. If we assume, unlike Moore, that Alice comes back in her original configuration and survives, we should still ask if she gets any benefit out of the bananas in the looking glass.

Researching this, I found that the main thing that makes bananas taste “banana-ish”, isoamyl acetate, does not have handedness: mirror bananas will still taste like bananas. Fructose, a sugar in bananas, does have handedness however: it isn’t the same when flipped in a mirror. Chatting with a chemist, the impression I got was that this isn’t a total loss: often, flipping a sugar results in another, different sugar. A mirror banana might still taste sweet, but less so. Overall, it may still be worth eating.

The next problem is a tougher one: flipping a potassium atom doesn’t actually make it immune to the weak force. The weak force only interacts with left-handed particles and right-handed antiparticles: in beta decay, it transforms a left-handed down quark to a left-handed up quark, producing a left-handed electron and a right-handed anti-neutrino.

Alice would have been fine if all of the quarks in potassium were left-handed, but they aren’t: an equal amount are right-handed, so the mirror weak force will still act on them, and they will still undergo beta decay. Actually, it’s worse than that: quarks, and massive particles in general, don’t actually have a definite handedness. If you speed up enough to catch up to a quark and pass it, then from your perspective it’s now going in the opposite direction, and its handedness is flipped. The only particles with definite handedness are massless particles: those go at the speed of light, so you can never catch up to them. Another way to think about this is that quarks get their mass from the Higgs field, and this happens because the Higgs lets left- and right-handed quarks interact. What we call the quark’s mass is in some sense just left- and right-handed quarks constantly mixing back and forth.

Alice does have the opportunity to do something interesting here, if she can somehow capture the anti-neutrinos from those bananas. Our world appears to only have left-handed neutrinos and right-handed anti-neutrinos. This seemed reasonable when we thought neutrinos were massless, but now we know neutrinos have a (very small) mass. As a result, the hunt is on for right-handed neutrinos or left-handed anti-neutrinos: if we can measure them, we could fix one of the lingering mysteries of the Standard Model. With this in mind, Alice has the potential to really confuse some particle physicists, giving them some left-handed anti-neutrinos from beyond the looking-glass.

It turns out there’s a problem with even this scheme, though. The problem is a much wider one: the whole story is physically inconsistent.

I’d been acting like Alice can pass back and forth through the mirror, carrying all her particles with her. But what are “her particles”? If she carries a banana through the mirror, you might imagine the quarks in the potassium atoms carry over. But those quarks are constantly exchanging other quarks and gluons, as part of the strong force holding them together. They’re also exchanging photons with electrons via the electromagnetic force, and they’re also exchanging W bosons via beta decay. In quantum field theory, all of this is in some sense happening at once, an infinite sum over all possible exchanges. It doesn’t make sense to just carve out one set of particles and plug them in to different fields somewhere else.

If we actually wanted to describe a mirror like Alice’s looking glass in physics, we’d want to do it consistently. This is similar to how physicists think of time travel: you can’t go back in time and murder your grandparents because your whole path in space-time has to stay consistent. You can only go back and do things you “already did”. We treat space in a similar way to time. A mirror like Alice’s imposes a condition, that fields on one side are equal to their mirror image on the other side. Conditions like these get used in string theory on occasion, and they have broad implications for physics on the whole of space-time, not just near the boundary. The upshot is that a world with a mirror like Alice’s in it would be totally different from a world without the looking glass: the weak force as we know it would not exist.

So unfortunately, I still don’t have a good “real life” story for a class about parity symmetry. It’s fun trying to follow Alice through a parity transformation, but there are a few too many problems for the tale to make any real sense. Feel free to suggest improvements!

A Week Among the Pedagogues

Pedagogy courses have a mixed reputation among physicists, and for once I don’t just mean “mixed” as a euphemism for “bad”. I’ve met people who found them very helpful, and I’ve been told that attending a Scandinavian pedagogy course looks really good on a CV. On the other hand, I’ve heard plenty of horror stories of classes that push a jumble of dogmatic requirements and faddish gimmicks, all based on research that if anything has more of a replication crisis going than psychology does.

With that reputation in mind, I went into the pedagogy course last week hopeful, but skeptical. In part, I wasn’t sure whether pedagogy was the kind of thing that could be taught. Each class is different, and so much of what makes a bad or good teacher seems to be due to experience, which one can’t get much of in a one-week course. I couldn’t imagine what facts a pedagogy course could tell me that would actually improve my teaching, and wouldn’t just be ill-justified dogma.

The answer, it turned out, would be precisely the message of the course. A pedagogy course that drills you in “pedagogy facts” would indeed be annoying. But one of those “pedagogy facts” is that teaching isn’t just drilling students in facts. And because this course practiced what it preached, it ended up much less annoying than I worried it would be.

There were hints of that dogmatic approach in the course materials, but only hints. An early slide had a stark quote calling pure lecturing irresponsible. The teacher immediately and awkwardly distanced himself from it, almost literally saying “well that is a thing someone could say”. Instead, most of the class was made up of example lessons and student discussions. We’d be assembled into groups to discuss something, then watch a lesson intended to show off a particular technique. Only then would we get a brief lecture about the technique, giving a name and some justification, before being thrown into yet more discussion about it.

In the terminology we were taught, this made the course dialogical rather than authoritative, and inductive rather than deductive. We learned by reflecting on examples rather than deriving general truths, and discussed various perspectives rather than learning one canonical one.

Did we learn anything from that, besides the terms?

One criticism of both dialogical and inductive approaches to teaching is that students can only get out what they put in. If you learn by discussing and solving examples by yourself, you’d expect the only things you’ll learn are things you already know.

We weren’t given the evidence to refute this criticism in general, and honestly I wouldn’t have trusted it if we had (see above: replication crisis). But in this context, that criticism does miss something. Yes, pretty much every method I learned in this course was something I could come up with on my own in the right situation. But I wouldn’t be thinking of the methods systematically. I’d notice a good idea for one lesson or another, but miss others because I wouldn’t be thinking of the ideas as part of a larger pattern. With the patterns in mind, with terms to “hook” the methods on to, I can be more aware of when opportunities come up. I don’t have to think of dialogical as better than authoritative, or inductive as better than deductive, in general. All I have to do is keep an eye out for when a dialogical or inductive approach might prove useful. And that’s something I feel genuinely better at after taking this course.

Beyond that core, we got some extremely topical tips about online teaching and way too many readings (I think the teachers overestimated how easy it is to read papers from a different discipline…and a “theory paper” in education is about as far from a “theory paper” in physics as you can get). At times the dialogue aspect felt a little too open, we heard “do what works for you” often enough that it felt like the teachers were apologizing for their own field. But overall, the course worked, and I expect to teach better going forward because of it.

At a Pedagogy Course

I’m at a pedagogy course this week. It’s the first time I’ve taken a course like this, and it has been really interesting learning about different approaches to teaching (which, as I keep being reminded, is very different from outreach!). It’s also really time-consuming: seven hours of class a day, with readings and lecture prep in the evening. As such, I haven’t had time to do a full blog post. Next week I’ll likely post some reflections about the course. Until then, here’s a slide from the practice lecture I gave:

Is Outreach for Everyone?

Betteridge’s law applies here: the answer is “no”. It’s a subtle “no”, though.

As a scientist, you will always need to be able to communicate your work. Most of the time you can get away with papers and talks aimed at your peers. But the longer you mean to stick around, the more often you will have to justify yourself to others: to departments, to universities, and to grant agencies. A scientist cannot survive on scientific ability alone: to get jobs, to get funding, to survive, you need to be able to promote yourself, at least a little.

Self-promotion isn’t outreach, though. Talking to the public, or to journalists, is a different skill from talking to other academics or writing grants. And it’s entirely possible to go through an entire scientific career without exercising that skill.

That’s a reassuring message for some. I’ve met people for whom science is a refuge from the mess of human interaction, people horrified by the thought of fame or even being mentioned in a newspaper. When I meet these people, they sometimes seem to worry that I’m silently judging them, thinking that they’re ignoring their responsibilities by avoiding outreach. They think this in part because the field seems to be going in that direction. Grants that used to focus just on science have added outreach as a requirement, demanding that each application come with a plan for some outreach project.

I can’t guarantee that more grants won’t add outreach requirements. But I can say at least that I’m on your side here: I don’t think you should have to do outreach if you don’t want to. I don’t think you have to, just yet. And I think if grant agencies are sensible, they’ll find a way to encourage outreach without making it mandatory.

I think that overall, collectively, we have a responsibility to do outreach. Beyond the old arguments about justifying ourselves to taxpayers, we also just ought to be open about what we do. In a world where people are actively curious about us, we ought to encourage and nurture that curiosity. I don’t think this is unique to science, I think it’s something every industry, every hobby, and every community should foster. But in each case, I think that communication should be done by people who want to do it, not forced on every member.

I also think that, potentially, anyone can do outreach. Outreach can take different forms for different people, anything from speaking to high school students to talking to journalists to writing answers for Stack Exchange. I don’t think anyone should feel afraid of outreach because they think they won’t be good enough. Chances are, you know something other people don’t: I guarantee if you want to, you will have something worth saying.

“Inreach”

This is, first and foremost, an outreach blog. I try to make my writing as accessible as possible, so that anyone from high school students to my grandparents can learn something. My goal is to get the general public to know a bit more about physics, and about the people who do it, both to better understand the world and to view us in a better light.

However, as I am occasionally reminded, my readers aren’t exactly the general public. I’ve done polls, and over 60% of you either have a PhD in physics, or are on your way to one. The rest include people with what one might call an unusually strong interest in physics: engineers with a fondness for the (2,0) theory, or retired lawyers who like to debate dark matter.

With that in mind, am I really doing outreach? Or am I doing some sort of “inreach” instead?

First, it’s important to remember that just because someone is a physicist doesn’t mean they’re an expert in everything. This is especially relevant when I talk about my own sub-field, but it matters for other topics too: experts in one part of physics can still find something to learn, and it’s still worth getting on their good side. Still, if that was my main audience, I’d probably want to strike a different tone, more like the colloquium talks we give for our fellow physicists.

Second, I like to think that outreach “trickles down”. I write for a general audience, and get read by “physics fans”, but they will go on to talk about physics to anyone who will listen: to parents who want to understand what they do, to people they’re trying to impress at parties, to friends they share articles with. If I write good metaphors and clear analogies, they will get passed on to those friends and parents, and the “inreach” will become outreach. I know that’s why I read other physicists’ outreach blogs: I’m looking for new tricks to make ideas clearer.

Third, active readers are not all readers. The people who answer a poll are more likely to be regulars, people who come back to the blog again and again, and those people are pretty obviously interested in physics. (Interested doesn’t mean expert, of course…but in practice, far more non-experts read blogs on, say, military history, than on physics.) But I suspect most of my readers aren’t regulars. My most popular post, “The Way You Think Everything Is Connected Isn’t the Way Everything Is Connected”, gets a trickle of new views every day. WordPress lets me see some of the search terms people use to find it, and there are people who literally google “is everything connected?” These aren’t physics PhDs looking for content, these are members of the general public who hear something strange and confusing and want to check it out. Being that check, the source someone googles to clear things up, that’s an honor. Knowing I’m serving that role, I know I’m not doing “just inreach”: I’m reaching out too.

This Week, at Scattering-Amplitudes.com

I did a guest post this week, on an outreach site for the Max Planck Institute for Physics. The new Director of their Quantum Field Theory Department, Johannes Henn, has been behind a lot of major developments in scattering amplitudes. He was one of the first to notice just how symmetric N=4 super Yang-Mills is, as well as the first to build the “hexagon functions” that would become my stock-in-trade. He’s also done what we all strive to do, and applied what he learned to the real world, coming up with an approach to differential equations that has become the gold standard for many different amplitudes calculations.

Now in his new position, he has a swanky new outreach site, reached at the conveniently memorable scattering-amplitudes.com and managed by outreach-ologist Sorana Scholtes. They started a fun series recently called “Talking Terms” as a kind of glossary, explaining words that physicists use over and over again. My guest post for them is part of that series. It hearkens all the way back to one of my first posts, defining what “theory” means to a theoretical physicist. It covers something new as well, a phrase I don’t think I’ve ever explained on this blog: “working in a theory”. You can check it out on their site!

Truth Doesn’t Have to Break the (Word) Budget

Imagine you saw this headline:

Scientists Say They’ve Found the Missing 40 Percent of the Universe’s Matter

It probably sounds like they’re talking about dark matter, right? And if scientists found dark matter, that could be a huge discovery: figuring out what dark matter is made of is one of the biggest outstanding mysteries in physics. Still, maybe that 40% number makes you a bit suspicious…

Now, read this headline instead:

Astronomers Have Finally Found Most of The Universe’s Missing Visible Matter

Visible matter! Ah, what a difference a single word makes!

These are two articles, the first from this year and the second from 2017, talking about the same thing. Leave out dark matter and dark energy, and the rest of the universe is made of ordinary protons, neutrons, and electrons. We sometimes call that “visible matter”, but that doesn’t mean it’s easy to spot. Much of it lingers in threads of gas and dust between galaxies, making it difficult to detect. These two articles are about astronomers who managed to detect this matter in different ways. But while the articles cover the same sort of matter, one headline is a lot more misleading.

Now, I know science writing is hard work. You can’t avoid misleading your readers, if only a little, because you can never include every detail. Introduce too many new words and you’ll use up your “vocabulary budget” and lose your audience. I also know that headlines get tweaked by editors at the last minute to maximize “clicks”, and that news that doesn’t get enough “clicks” dies out, replaced by news that does.

But that second headline? It’s shorter than the first. They were able to fit that crucial word “visible” in, without breaking the budget. And while I don’t have the data, I doubt the first headline was that much more viral. They could have afforded to get this right, if they wanted to.

Read each article further, and you see the same pattern. The 2020 article does mention visible matter in the first sentence at least, so they don’t screw that one up completely. But another important detail never gets mentioned.

See, you might be wondering, if one of these articles is from 2017 and the other is from 2020, how are they talking about the same thing? If astronomers found this matter already in 2017, how did they find it again in 2020?

There’s a key detail that the 2017 article mentions and the 2020 article leaves out. Here’s a quote from the 2017 article, emphasis mine:

We now have our first solid piece of evidence that this matter has been hiding in the delicate threads of cosmic webbing bridging neighbouring galaxies, right where the models predicted.

This “missing” matter was expected to exist, was predicted by models to exist. It just hadn’t been observed yet. In 2017, astronomers detected some of this matter indirectly, through its effect on the Cosmic Microwave Background. In 2020, they found it more directly, through X-rays shot out from the gases themselves.

Once again, the difference is just a short phrase. By saying “right where the models predicted”, the 2017 article clears up an important point, that this matter wasn’t a surprise. And all it took was five words.

These little words and phrases make a big difference. If you’re writing about science, you will always face misunderstandings. But if you’re careful and clever, you can clear up the most obvious ones. With just a few well-chosen words, you can have a much better piece.